ame 441al course handout - fall 2011

AME 441aL SENIOR PROJECTS LABORATORY

FALL 2011

Lectures: 12:30 1:50 T 12:30 1:50 W

ZHS 159 MHP 105

Laboratories: 9:00 11:50 TTh 9:30 12:20 MW

BHE 310 BHE 310

Professors: Dr. C. Radovich Dr. Y. Staelens

RRB 202 BHE 317

(213) 740-5359 (213) 740-7754

[email protected] [email protected]

Laboratory Manager: Benjamen Bycroft

BHE 301, (213) 740-4304

[email protected]

Laboratory Technicians: Rodney Yates Ewald Schuster

BHE 310, (213) 740-4304 RRB 114, (213) 740-1078


Teaching Assistants: Winston Chiang Tyler Davis


Jihyun Kim Yeh Lin


Recommended Texts (not required):

Beckwith, T.G. & R.D. Marangoni. Mechanical Measurements, 6th ed, Addison Wesley.

Holman, J.P. Experimental Methods for Engineers, 7th ed., McGraw Hill.

Atchison, S. & B. Kennemer. Using Microsoft Project 2010, Que Publishing.

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Important note to all students registered for AME 441aL:

This semester we have close to 120 students registered for the course. In a departure from prior

years, we have had to cleanly divide the class into two more-or-less numerically equal groups.

One group meets in the lab on Mondays and Wednesdays with a lecture on Wednesday. The

other group meets in the lab on Tuesdays and Thursdays with a lecture on Tuesday. The lecture

sections will be used to discuss course material, introduce and review concepts, and for the oral

presentations given by each group. You must attend the lecture section for which you are

registered (T or W from 12:30 to 1:50 pm); all of them. You are also expected in the lab during

your registered time slots, where weekly verbal reports will be given. Attendance during the oral

presentations will be taken and points subtracted for each absence after the first; late arrivals are

the same as a no show.

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Senior Projects in Aerospace and Mechanical Engineering

Fall 2011

I. Introduction

The aim of this course is to introduce the student to some of the basic ideas of experimental work. The emphasis is on project work where one's ingenuity and initiative are a major factor in success. It is as close as one can get, in a teaching situation, to the responsibilities of an industrial research project. It gives the student a taste of the type of problem(s) she/he is likely to encounter upon leaving school.

Students work in groups of two on a project of their choice for the entire semester. Ideally, topics for these projects are provided by the students themselves. Think about where you want to be next year and make this project the centerpiece of your academic and budding professional portfolio. However, projects can be selected from a number of ideas suggested by the faculty and provided in this handout.

The extent of the subjects covered is quite broad. Project topics have ranged from such traditional areas as fluid dynamics, structural mechanics, heat transfer, and dynamic control, to rather obscure and arcane studies on fishing line motion, plant growth in varying pressure environments, anti-lock brakes and the like. The primary requirement in the selection of a topic is that the student must be interested in it. More pragmatically, design, construction and testing should be accomplished within one semester given the constraints of the lab facilities and a set financial budget which will be discussed shortly.

Before work can begin on any project a formal written proposal, including a timetable and budget, is required. On Wednesday, August 31st at 2 pm in RRB 101 the preliminary proposal is due; this will be returned promptly so that comments and required changes can be addressed. The final proposal is to be submitted by Wednesday, September 7th at 2 pm in RRB 101. If approved, work on the project can begin.

Written group progress reports are due every 2 weeks starting Wednesday, September 21st in RRB 101. During each lab session, a few groups will be chosen to describe their progress orally to the instructors. One Final Report of publishable quality will be required by each group at the end of the term, Friday, Dec. 2nd at 5pm in RRB 101. Each group will also be required to give an oral presentation of their work to the rest of the class. Students will be evaluated upon the quality and content of their reports and presentation as well as their performance in the laboratory; this includes cleanliness of work areas and attendance in the scheduled lecture/laboratory sessions.

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II. AME Lab Procedures and Protocol

Safety and Space Management

Closed-toe shoes are required in the lab at all times.

Safety precautions (gloves, eye protection, hair ties, etc.) are mandatory. Ask a staff member if

you are unsure of any safety precautions you should be taking when working in the lab.

According to University rules, students are not allowed in the lab without supervision. Therefore,

all experiments must be performed within the scheduled lab times.

Store your personal belongings out of walking paths under work tables for instance. It is

important to keep a clear and safe walkway through the laboratory.

Keep the lab clean. No food or drinks in the lab area. You are welcome to have food or drinks in

the hallway, near the stairs, or in the BHE 301 presentation room (outside of AME 341 lab hours).

Return all lab equipment to its original location (cables, beakers, drill bits, etc.).

There is a small engineering library in the BHE 301 presentation room. These resources are to be

shared and are not to leave the BHE 301 presentation room.

Supply Room and Device Access

Access to the BHE 301a supply room is allowed only with approval of an AME 441 staff member.

Any/all resources and devices that leave the Supply Room must be approved, checked out, and

signed for by an AME 441 staff member.

Please report any/all broken or non-functioning equipment and devices to the staff. This is

extremely important, and will save everyone time and trouble in the future!

When requesting equipment, students must be prepared to give all the pertinent characteristics they require so that the staff can act on the requisition effectively.

On some occasions, it becomes necessary to share some equipment with other groups. Under these circumstances all parties involved are expected to be considerate and cooperative.

When requesting to have parts fabricated/machined, ensure that your designs are complete

design by trial and error will not be allowed. Be prepared to thoroughly present and explain your

design in order to facilitate the approval and scheduling of part fabrication/machining.

Computer/Printing Rules

Login Name: JStude Password: AMElab

Do not customize any computer workstations. This includes modifying the desktop, any/all

computer settings, installing any software without staff approval.

Save files only in the following directory: D:\home\JStude. Files in other locations will be

deleted.

Remember to save your work to the computers hard drive before moving it to a USB key or

portable storage device.

Printers are available only for printing of assignments, reports, and required usage for AME 441.

This does not include lectures notes, or reprinting of materials provided to you.

When done with a computer workstation, log off and turn off the monitor.

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III. Facilities

The AME Lab has a low-turbulence, open-circuit wind tunnel located in BHE 301. The test section measures 46 x 46 x 91 cm, and can provide freestream velocities from 3 m/s to 46 m/s with less than 1% variation from the mean. The turbulence level is less than 0.25%. It is equipped with two force balances, both 2 components: one is capable of measuring lift and drag forces of up to 67 N and 35 N, respectively, and the other to 12 N. Also, as part of a Senior Design Project, a new water channel was constructed in BHE 110. The test section of this water channel measures 18 cm x 20 cm x 91 cm, and has a test velocity range of 5 to 25 m/s. Force measurements (e.g., lift, drag) can be made in this water channel, and flow visualizations can be performed through the transparent, acrylic test section walls.

Other facilities available for use are: a pipe flow apparatus to study convective heat transfer (in pipes); a cross-flow heat transfer apparatus to determine the properties of various heat transfer devices (heat exchangers) mounted in-line; a device for applying precise buckling and bending loads to rods and beams; instrumentation to determine the dynamic vibration of various beam configurations; and an oscillating pendulum apparatus for studying second order system dynamics, and for studying coupled modes of vibration of various compound pendulums.

Other small facilities like drop tanks, towing tanks, shock tubes, and vacuum chambers are also available. In the past, some students, working on certain projects, have been granted the use of some of the department's more advanced research facilities.

The AME Lab provides PCs for data acquisition and analysis. Instrumentation is available in the laboratory including low-power lasers, digital image and video recorders, high-speed cameras, hot-wire

anemometers, various pressure transducers, etc. If the required instrumentation is not readily available in the lab, they can often be procured from other departments on a loan basis (e.g., a micropipette could be borrowed from the Biology department).

IV. Budget

Each student is allotted approximately $75 for the purchase of expendable materials. The total amount of funding for a project will be based on the budget submitted with the proposal and may exceed this amount if it is deemed necessary for the project's success. A wide selection of hardware, raw materials and tools such as screw drivers, drills, circular saws, sanders, etc. are already available in the supply room. Should you need to make a purchase, follow the guidelines below:

Prior to making any purchase, approval is required by either Dr. Staelens or Dr. Radovich. Pre-approval is required if you want to be reimbursed. The detailed procedure for making purchases from online retailers will be discussed during the first week of class. In general, you will prepare an order, print the detailed summary but do not submit the order confirmation. Then, bring the printout to your

instructor for a signature and deliver the order summary to Silvana Martinez in RRB 101.

The student may make smaller cash purchases and she/he will be reimbursed upon presentation of an original receipt; again, get pre-approval from your instructor. Items from the Engineering Machine Shop

(KAP Basement), Electronic Store (OHE 246), and Chemistry Store (SGM 105) can only be obtained on an Internal Requisition. Cash purchases from these places will not be reimbursed.

No reimbursements will be made if the above procedures are neglected. No exceptions!

V. Grading

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Grades are based on both individual and group performance. Marks will be assigned to all written reports and the oral presentation. All these are expected to be of a quality that reflects the care and professionalism with which the student conducts her/his work. Requirements for all written reports and a sample grade sheet for the oral presentations are provided in Section V and Appendices A through D. The order of the oral presentations is to be determined by lottery.

Students will be graded on their performance in the laboratory. To facilitate this, as well as to help guide the direction of each group's research, conferences with one or more instructors will be held at regular intervals. During these conferences, current work and problems are to be discussed and evaluated. The instructors should be notified immediately of any difficulties in the research, as delayed notification may have an adverse effect on performance assessment. It is essential that these projects are worked on continuously; waiting until the last few weeks will surely be detrimental to your grade.

All students are expected to attend the oral presentations on Tuesdays or Wednesdays at 12:30 p.m. You are required to attend the Lecture session that you are registered for. Attendance will be recorded

and one absence will be permitted, use it wisely. A 10% penalty will be applied to your oral presentation score for each additional absence. Arriving late or leaving early counts as an absence.

Each student is required to keep a laboratory notebook as described in Section V. This is to be turned in with the final report at the end of the semester. This year we have put added emphasis on the maintenance of this laboratory notebook incomplete and untidy entries will result in a 5% penalty, applied to your final grade.

Each student must also complete the mandatory lab safety training within the first week of labs. Lab work on your project will NOT be permitted until this training has been completed. Furthermore, failure to complete the training within the announced time frame will result in a 5% lab performance penalty.

The complete grade distribution is detailed in Table 1.

Table 1. Final Grade Weight Distribution (%)

Proposal 10

Progress Reports 10

Oral Presentation 20

Lab Performance 20

Final Report 40

TOTAL 100

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VI. Deliverables

The first written requirement is the Project Proposal. At a minimum, the proposal should follow the guidelines provided in Appendix A. Only one per group is required. Preliminary proposals are due on Wednesday, August 31st at 2 pm in RRB 101. Early submission of the preliminary proposal is strongly encouraged, since major rewriting is often required for the final proposal to be approved. The deadline for submission of the final proposal is Wednesday, September 7th at 2 pm in RRB 101. It is also recommended that you discuss any ideas and/or approaches with your instructors, TAs and lab staff during this process.

It is not uncommon for proposals to be rejected. Students whose projects are not approved will be given an extra week to submit a new proposal but can no longer receive full credit. Work on the project can begin once the project is approved.

A progress report is due every other Wednesday before 2 pm, starting September 21st. Only one per group is required and the contents should follow the suggested guidelines presented in Appendix B. It is anticipated that a total of five progress reports will be handed in through the semester. These will be

graded mainly on the amount of progress achieved by the group.

The Final Report is due Friday, December 2nd at 5:00 pm in RRB 101. Each group is required to submit one final report. Late reports will be penalized (-10% per day, including the weekend). The suggested format for the final report can be found in Appendix C. Although one Final Report is turned in per group, each student is required to submit the Group Evaluation Form found in Appendix E. Print this form and hand it in Friday, December 2nd at 5:00 pm in RRB 101. There will be separate drop boxes for the Group evaluation forms and the final reports.

Each student is also required to maintain a laboratory notebook. It should contain all possible methods of solving problems that arise, as well as the details of these problems. Raw data, calculations, construction and set-up drawings, uncertainty analysis, etc., should all be contained in this notebook. It should be kept neat and legible so that an individual assigned to take over the project at a later time can easily continue the project. In the back of the notebook, a log of hours spent on the project should be kept as well, with a brief description of what was done at particular times. This notebook is to be submitted with the final report and will be graded.

As mentioned earlier, the order of oral presentations is to be determined by lottery. Presentations will be 20 minutes long total, including questions. The standard visual aid to be used will be a computer with a projector. A sample grade sheet for the oral presentation can be found in Appendix D. On your presentation day, arrive at lecture 15 minutes prior to the start of class (i.e., 12:15 pm) and upload your PowerPoint file to the class computer.

All documents are to be typed, stapled or clipped, and a hard copy must be submitted. Do NOT email

reports. The use of fat, three-holed binders is discouraged because, in large numbers, they are cumbersome for us to handle. Include your Group #, date, title and names of the authors.

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VII. Awards and Recognition for Outstanding Student Design Projects

The AME Department takes great pride in the quality of the research work produced in the Senior Projects Laboratory. At the end of the year, a select few may be recognized for their ingenuity, craftsmanship and significant contributions towards the fields of science and engineering. The best of these will be awarded the John Laufer Memorial Prize that is in honor of the founder and first chairman of the AE Department. Descriptions for each of the prestigious AME awards are provided below. These awards all include a plaque/certificate and a cash prize. Prizewinning groups are encouraged to compete in the AIAA Western Region Student Conference; the winner will go on to represent the region in the AIAA National Student Competition. It is expected that every student will strive to produce research work worthy of national recognition for excellence.

John Laufer Memorial Prize

John Laufer established the Aerospace branch of USCs AME Dept in 1964 and served as chairman of the Department for 19 years. He was an internationally known experimentalist in fluid

mechanics and had an illustrious career that included spans at Cal Tech, NBS and JPL, in addition to the many years he spent at USC. He was instrumental in developing the Sr. Experimental Projects Laboratory, a culminating experience for all students within the AME Department. In his honor, the Department established the John Laufer Memorial Award to recognize the student or students with the most scientifically meritorious project in the Senior Experimental Projects Laboratory.

Bleeker Award - For Craftsmanship

Al Bleeker was an enthusiastic, dedicated supporter of undergraduate experimental studies. As a friend, technician and teacher, Al counseled over two generations of laboratory students. The faculty, students and friends of the AME Department as a tribute to Als contributions established this award, for excellence and imagination in the design and construction of experiments during the senior year laboratory course.

Aerospace and Mechanical Engineering Student Achievement Award

The Achievement Award is given to the students in the AME Senior projects laboratory who have shown outstanding ingenuity and performance in the design, construction and testing of their senior project.

On the following page, a list is provided showing those that have earned their way into the AME Senior Project Laboratory Hall of Fame a record of those whose work was recognized as being of the highest quality, and the AME and national awards which they received.

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AME Senior Project Laboratory Hall of Fame

Laufer Memorial Prize 2010 Weston Thompson, James Yuan

2009 Brennan Barker, Kevin Brashear

2004 Adam Garofalo, Scott Keen, Margaret

Wharton

2003 Stephane Gallet, Jonathon Hartley

2002 David Lazarra

2000 Amy Green

Bleeker Award

2010 Alexander Sobel, Ahmet Taner

2009 Joseph Hu, Cody Ives, Mark Leffingwell

2004 William Kaplan, Jennifer Tsakoumakis

2002 Brian Bjelde, Brian Eccles

AME Student Achievement Award 2010 Matthew Dung, Michael Jacobs, Alec

Winetrobe

2009 David Anderson, Erin Kampschroer

2004 Zeeshan Ahmed, Daniel Frohlich

Student Competition Awards

2010 Ryan Jansen, Eric Teegarden 1st

- AIAA Western Region, Undergraduate

Matthew Dung, Michael Jacobs, Alec

Winetrobe

1st

- AIAA Western Region, Team

2009 Justin Crawford, Andrew Newman-Dilfer 2nd

- District D ASME Design Competition

2008 Benjamin Bycroft 1st

- Viterbi KIUEL Senior Design Expo

Joe Lubinski, Kedar Naik 2nd

- USC Undergraduate Symposium for Scholarly and

Creative Work, Physical Sciences

2005 Sergio Ibarra, Antonio Trevilla, Erin

Wickstrand

1st

- Region IX ASME Design Competition

2003 James Parle 1st

- AIAA Western Region

Sonya Collier, Cheryl Ham 3rd


2002 Brian Bjelde, Brian Eccles 1st


2001 Amy Green 1st

- AIAA National Student Conference

2000 Amy Green 1st


Best Technical Award, Intl. Astronautics Federation (Brazil)

Al Knight 2nd


1995 Steve Vargo 1st


1994 Steve Vargo 1st


1993 1st

, 2nd

and 3rd

place AIAA Western Region

1987 Ira Astrachan, Steve Fourier 1st


1985 Melissa Dixon 1st


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Appendix A: Suggested Format for Proposal

Section Title No. of Pages

1. Introduction/Historical Background 1

2. Theory/Basic Equations 1-3

3. Experimental Setup/Procedure (including a sketch of the apparatus) 1-4

4. Cost Estimate 1

5. Timetable 1

6. Reference List 1/2

The objective of the proposal is to convince the reader that your project will provide useful

information and can be done within the time, budget, and other constraints given. The knowledge that one stands to gain from it is, of course, not expected to be of the sweeping, general, great-benefit-to-mankind type, but rather to be specific and limited in scope. The proposal should be no more than 10 pages of typed double spaced text.

The reader should be convinced that you know what you are talking about in terms of information currently available on your topic and what you want to do to advance this knowledge. Your goal must be explicitly stated. Reference previous and current work and give legitimate reasons for conducting the experiment.

You should also have a clear picture of how you are going to conduct your experiment. Perform rough calculations to enable you to design your apparatus in a logical manner and to estimate, roughly, the magnitude of your expected results; i.e., try to determine what you need by calculation rather than just guessing. What facilities and equipment will you be using? How large will the model be? What are the important parameters? What kind of data will be taken? You should have researched your topic in enough detail and performed some initial calculations to be able to answer these types of questions. Include a sketch of the set-up as you imagine it will be as well as calculations, graphs and figures that will help explain what you will do.

The cost estimate must provide an accurate account for the total cost of your project. It should

include all equipment, devices, materials, etc. that are required to perform and complete your experiment. This should be presented in a tabular format. A clear distinction must be made between the devices and materials that are currently available in the AME Lab and what needs to be purchased using your allocated AME 441 budget.

The timetable should be presented as a Gant chart, highlighting the project milestones required for completion, the resources available, and the course deliverables due throughout the semester. MS Project should be used to create this schedule; this program is available on the AME Lab computers as well as in all the USC student computer labs. Helpful how-to hints will be discussed during lecture and a tutorial will be available on Blackboard.

Remember to write your proposal in a manner that can be easily followed by a reasonably competent engineer who is not necessarily specialized in your project's field. A good rule is to define any terms or concepts that you were not familiar with before you started your literature search. As a test, have one of your classmates (not a group mate) read your proposal to see if she/he understands, and can picture what you want to do!

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Appendix B: Format for Bi-Weekly Progress Report

Title of Project

Group # and Student Names

Progress Report for the Period Starting MM/DD/YY and Ending MM/DD/YY

Progress reports should be written in third person past tense, as all technical communications should be. The task of writing the progress report for the group should be distributed evenly between the group members. These reports will be graded partially on form but mostly on content and the amount of progress you have made in the lab. Note: preparing an oral presentation is not lab progress.

In general, progress reports should include the following:

1) A brief description of the project scope. This should be 1-2 sentences only and serves to remind the reader of the overall objective(s). This blurb will likely remain unchanged for the entire semester; i.e., used on all progress reports.

2) The main contents of the progress report should detail specifically what was accomplished during the previous fortnight. This may include calculations, a description of designed components and an accompanying image any useful information that will help the staff assess your progress. If data were acquired, a plot of the results should be presented and discussed. If any issues or problems were encountered, they should be addressed (what happened, plans for mitigation and

effect on the timeline).

3) A concise explanation of the tasks to be performed during the upcoming weeks.

4) Each progress report should include an up-to-date timeline (Gant chart).

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Appendix C: Suggested Format for Final Report

Section Title No. of Pages

Abstract (on title page) 1

Introduction 2-4

Experimental Technique 2-4

Results 3-6

Discussion 2-3

Conclusion 1

References 1

Appendices No more than 5

Note: No more than 25 pages of typed double spaced text, including appendices.

Assume the reader knows nothing about your work! The final report should stand alone with no references to your proposal or progress reports. (You may of course reference other papers or books.) The introduction should state the goal/objective, give some historical background and/or the state of the art of the subject, and any theoretical derivations pertinent to the project.

The experiment technique section should give the important details of the set-up (a schematic must be included) as well as the procedure. Mention all the equipment used, type of data taken, how the data was processed, etc. When writing this section, keep in mind that you want to give the reader

the impression that you were careful when you took your measurements and your data is reliable. Towards this end you can mention your estimates of uncertainty and accuracy without going into excessive detail. (Detailed uncertainty analysis can be put into an Appendix and should definitely be in your lab notebook!!!) Do not go into a narration of all the trouble you went through to get to your final set-up!

Results and Discussion can be two separate sections or one. It can even be subdivided into the different aspects of the investigation. The only requirement is that you present your results and then discuss them in a manner that can be easily followed. This is by far the most important part of your

report and should be worded carefully so as to enhance the virtues of your work.

In the Conclusion, assess whether you have achieved your goal/reached your objective as stated in the Introduction. You may restate your important findings briefly. Also, you could suggest an

alternate approach to solving the same problem or, talk about improvements to the work and applications.

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Appendix D

AME-441 Senior Projects Laboratory

Oral Presentation Grade Sheet

Group # Date:

Title of Project:

Name(s) of Speakers:

Grade for each category is based on the scale shown below.

Grade Comments

1. Organization and Delivery (Was project clearly defined? Continuous

thoughts? Speech easy to understand?

Visual aids: timing, sufficient number of

slides, neatness, clarity, etc.)

(35) 2. Technical Content (Scientific merit appraised? Symbols and

parameters defined? Technically sound arguments? Logical methods of

experimentation and evaluation? Etc.)

(50) 3. Overall Performance (Did presentation hold audiences

attention? Questions answered, etc.)

(15) Total Score (100)

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Appendix E

AME-441 Senior Projects Laboratory

Group Evaluation Form

Although one Final Report is turned in per group, each student is required to submit the following Group Evaluation Form. Turn this form in Friday, December 2nd at 5:00 pm in RRB 101. There will be separate drop boxes for this form and the final report.

Use this form to evaluate the contributions made to your AME 441 Senior Project by all members of your group (including yourself). In the table provided below, print the names of all group members and assign a score for each performance category. Rank each category on a scale of 0 to 4 (0 being the lowest; 4

being the highest); don't forget to rate your performance as well. You may also provide specific comments for each team member in the space provided. The scoring guideline is as follows:

0 = Poor, would have been better solo

1 = Below average, rarely met expectations

2 = Average, fulfilled expectations of the group

3= Above average, occasionally exceeded expectations

4 = Outstanding! Often exceeded expectations

Group # Project Title:

Team Member NAME

Cooperation Dependability Participation Quality of

Work Interest and Enthusiasm

your name

Comments:

Comments:

Comments:

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AME 441a Project Suggestions Fall 2011

Project 1. ASME 2012 Student Design Competition: Energy Relay

Advisor: Profs. G. Shiflett, C. Radovich and Y. Staelens Difficulty: Difficult

The complete 2012 ASME Student Design Competition information, including contest rules and FAQs, is available at: http://www.asme.org/events/competitions/student-design-competition.

Problem Statement

Providing energy to a world with a growing population and rising expectations is a challenge that engineers must embrace and solve. So many factors must be considered and balanced: cost, efficiency, resource availability, environmental impact, sustainability, and more. Many different potential solutions

are being proposed and developed. While the winners have yet to be determined, it is safe to assume that the future will include a wide variety of solutions that together will power our planet.

Providing transportation energy is a major piece of the overall energy challenge, and is the focus of the

2012 Student Design Competition. Practicing engineers in transportation areas are developing a variety of technology options and looking to integrate these technologies. You must do the same for the competition described below.

Project Task: Design four self-propelled devices which can collectively complete a relay race in the shortest period of time. Each device must contain an on-board energy source and trigger the motion on the next device. The devices will compete on a course as shown below. Bonuses will be awarded for devices having different energy sources and for initiating subsequent devices.

Project Guidelines:

1. The track will be a straight path as shown in Fig. 1 (see internet link previously stated). Surfaces will not be defined and may include hard floors, carpet and/or anything else that could be encountered at the venue. There are no barriers on the sides. The sides will be defined by tape.

2. Before each test run, one device will be placed with its leading edge on the starting line, with the subsequent devices located on transition lines 1-3.

3. Students will initiate the first device in the relay by toggling a clearly labeled on/off switch. Subsequent to this all devices must operate autonomously.

4. The motion of devices 2-4 in the relay must be initiated by the prior device, after it has traversed its segment of the course.

5. Each of the four devices may be powered by a different type, or unique combination of, energy source(s). Note that devices using combustion, fossil fuels, or nuclear power sources, as well as live animals, are prohibited in this competition.

6. Each device, as it would be placed on the track, must fit in a box with internal dimensions measuring 100 mm by 100 mm by 200 mm. Each device must arrive at the contest venue in a separate box, satisfying the above dimensions, provided by the team.

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Project 2. Flow on a Rotating Disc

Advisor: Prof. T. Maxworthy Difficulty: Moderate

Several variations of this project are possible. One will be described here; others can be discussed in conference with Prof. Maxworthy.

These flow types have several interesting applications. Foremost is their use in industrial spray-painting situations, e.g., automobile painting. A number of artists have used the technique to produce interesting abstract paintings. The technique is used to manufacture thin films for various applications.

In the present case, a rotating disc has a circular dam placed at its center. Fluid fills the space behind the dam to a known depth. The disc is then rotated at known rotation rate, the dam is raised and the fluid moves radially outwards. The position of the front is measured as a function of time. When the disc is not rotating, the theory for the front motion is well known. As far as we know, this is not true for the rotating

case. The similar problem of a two-dimensional sheet of fluid flowing down a slope is also well studied and has shown that the front becomes unstable, as depicted below. Is this scenario possible for the rotating case?

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Project 3. Thermals with Negative Buoyancy


Most applications of thermals consider the case where the buoyancy acts in the direction of the initial motion; e.g., clouds, forest fires, etc. In the opposite case, the buoyancy acts to oppose the initial impulsive motion; e.g., in volcanic explosions or, in some plants that broadcast their seeds by ejecting them vertically. The following two projects look at slightly different models for these processes:

Project 3A:

In a tank of fresh water, generate a vortex ring of salt water. If the initial velocity is U, the hole diameter D and the density difference , then one would expect that the flows would be different for large or small values of U2/ D (a Froude number). For large values, a vortex ring should form initially which then collapses as the ring slows. For small values, a dense puff of heavy fluid forms that soon reverses and falls to the bottom of the tank. Photograph the history of the thermal motion and determine how its velocity varies with time. A typical apparatus is shown below but there are other ways to generate the initial ring that you might want to consider.

Project 3B:

In air, project a small volume of a granular material vertically upwards with velocity U. Observe the motion photographically for various cases of velocity, volume and density. A possible type of gun is shown below although other designs might be better. See TM for photographs of seed pods bursting and thereby broadcasting their seeds.

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Project 4. Heat Transfer from a Heated Object

Advisor: Prof. T. Maxworthy Difficulty: Easy

We have available a commercial wind tunnel designed to look at heat transfer from a heated cylinder in a bundle array. Reference: any textbook on Heat Transfer.

Design a rotating, circular-cross-section test-cylinder to be placed in the test section and measure its

heat transfer characteristics over a range of parameters ( ). Especially include the non-rotating case so you can compare with available data.

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Project 5. Quasi-two-dimensional Flow (2D) in a Flowing Soap Film


Recently, there has been some interest in trying to model 2D flow in a flowing soap film. The apparatus consists of a supply of soapy water that is allowed to flow between two parallel nylon strings. We would like to study the oscillation of a flat plate to simulate the motion of the tail of a fish. The paper by Schnipper et al. has studied this but for some curious reason used the size of the support rod as a length scale. It is more correct and conventional to

use the length of the plate ( ) and/or the amplitude of oscillation ( ). This scaling needs to be checked in more detail. By placing small particles in the film one can use our existing software to measure the velocity field in the film at the same time as observing the film thickness, as in the reference photos. A sketch of a possible setup is shown. The apparatus exists, but is in poor condition, and the oscillating plate needs to be incorporated.

Reference Schnipper et al., Vortex wakes of a flapping foil, Journal of Fluid Mechanics, V. 633, pp 411-423.

Project 6. Water Cooler Loader

Advisor: Profs. Y. Staelens and C. Radovich Difficulty: Moderate

Drinking water should not require much effort (or a gym membership)! Design a device capable of

loading a water bottle (say, 5 gal) on top of standard types of coolers so that the task can be accomplished with minimum effort by a single person. The system should be light, portable, safe and easy to use. It should also allow for easy transportation of full water bottles from a storage location to the cooler.

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Project 7. Shock Waves through a Bubbly Liquid

Advisor: Prof. V. Eliasson Difficulty: Moderate

When a weak shock wave passes through a bubbly liquid the bubbles serve as nucleation sites for cavitation. Here, we would like to come up with a method to generate bubbles in a water-filled cavity inside a transparent plastic material (maybe electrolysis?). Then, an impact will be generated by using a gas gun already in place in Prof. Eliassons lab. The task is to find out how the water to air ratio influence the cavitation taking place, plus, determining whether or not the plastic material will

crack.

Project 8. Shock Wave Impact on an Inclined Liquid Surface

Advisor: Prof. V. Eliasson Difficulty: Moderate

We want to study the effect of inclination angle, , of a water surface as a shock wave impacts and transmits through the air/water interface. You need to build a transparent shock tube, then use high-speed photography and pressure sensors to determine the effect on the transmitted shock wave of the

inclination angle. High-speed photography equipment and pressure sensors are available in Prof. Eliassons lab.

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Project 9. The Stability of a Shocked Interface

Advisor: Profs. T. Maxworthy and V. Eliasson Difficulty: Moderate

When a pressure pulse (shock wave) passes through an interface (e.g., from water to air) it causes a disturbance which, as far as I know, has not been studied in detail. Set up an apparatus to study this using some of the equipment in Prof. Eliassons lab. A possible test rig is shown below. A sharp impulse to the bottom of the tube generates the shock wave and a high speed camera is used to record the resulting disturbance. Introduce known disturbances to see how they grow.

Project 10. Sandstorms and Solar Panels

Advisor: Profs. C. Radovich and Y. Staelens Difficulty: Moderate to Difficult

The Department of Water and Power proposes to cover a large expanse of Owens Lake with solar

panels. Read: http://www.reuters.com/article/idUSTRE61A04M20100211. Owens Lake has been drained

by usage from metropolitan LA, and DWP currently sprays water over the dry bed to reduce the intensity of

sand/dust storms. The presence of solar panels may help to trap the water and keep the atmosphere

moist, as well as generating electricity. The question arises now, how should the solar panels be

constructed and arranged so that their operation is not compromised by the wind-driven dust.

This project has several possible areas for investigating. A general question might be: how does one

arrange an array of multiple flat plates so that ground dust is not lifted onto their faces when the winds

rise? Lift them up? If so, then how high? How does the dust affect the power output of the solar panels?

Do they need to be cleaned regularly? If so, how? Put wipers on them? Install solar-powered mini-blowers

on them? Have the panels tilt so they can clean themselves? What is the financial impact of such a device?

Some of these ideas have merit, others not. Experiments in a water channel or in the student wind tunnel

can be formulated to investigate some of these problems.

Research items may include: composition of dust, strength of wind, calculation of atmospheric

boundary layer thickness, scaling of appropriate experiments. Design elements include: number and

geometry of plates and their degrees of freedom, dust removal or prevention strategy, simple decisive test

to answer specific questions, given the design.

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Project 11. Breakup Radius of a Disturbed Liquid Sheet

Advisor: Prof. C. Radovich Difficulty: Moderate to Difficult

As depicted in the figure below (from Clanet and Villermaux 2002), an axisymmetric radially expanding

liquid sheet can be produced by directing a laminar jet of water onto a stationary flat disk. In this figure, U

is the velocity of the incoming jet, D is the jet diameter, and Di is the diameter of the impact disk (D < Di).

The edge of the sheet is defined by the radius R, where the sheet disintegrates into droplets. G. I. Taylor

derived the following analytical expression for the breakup radius using the density of water (), volume

flow rate (Q) and the surface tension of water against air ().

Through experimentation, J.C.P. Huang determined that the breakup radius of a radially expanding

liquid sheet varied with the Weber number a dimensionless ratio of inertial and surface tension ( )

forces, . Huang found that the breakup radius followed when .

Note, instead of using an impact disk Huang impinged two coaxial streams. Thus, which,

when applied to Eq.1, aligns with Taylors prediction.

Both Taylor and Huang found that measurements of the breakup radius were typically some value less

than that predicted by Eq.1. It is believed that disturbances imposed on the liquid sheet produced this

result by accelerating the disintegration process. Some possible sources are the surface roughness of the

impact disk and/or vibrations in the water jet delivery system.

The goal of this project is to determine what effect external disturbances can have on the breakup of a

liquid sheet. The impact disk and a controllable means for disturbing the liquid sheet must be designed and

implemented; an array of nozzles and a water reservoir already exist, although a new apparatus could be

constructed. Test variables may include the disturbance frequency, disturbance strength and the Weber

number. Measurements of the breaks radius can be made with images from a camera.

References Clanet, C., and E. Villermaux. Life of a Smooth Liquid Sheet. Journal of Fluid Mechanics 462 (2002): 307-340.

Huang, J.C.P. The break-up of axisymmetric liquid sheets. Journal of Fluid Mechanics 43 (1970): 305-319.

Taylor, Geoffrey. The dynamics of thin sheets of fluid II. Waves on fluid Sheets. Proceedings of the Royal Society of London 253A (Dec. 15, 1959b): 296-312.

Taylor, Geoffrey. The dynamics of thin sheets of fluid III. Disintegration of fluid sheets. Proceedings of the Royal Society of London 253A (Dec. 15, 1959c): 313-321.

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Project 12. Object Detection and Image Focusing


Consider a camera and lens setup that has a finite depth of field. The depth of field represents a distance from the focal plane in which the lens is able to see clearly. Using centimeters as the unit of length, the focal plane is located, by definition, at cm. Any object located outside of the focal plane ( ) will appear blurred, as shown in the figure below.

Given that the depth of field is finite, if an object were randomly placed into the field of view it will likely be out of focus. The goal of this project is to design an apparatus (and image analysis routine) that can detect a foreign object and bring it into focus. This experiment will be restricted to an optical setup with a fixed focal length. Some possible design considerations include the size of the object of interest and motion of the object (in the x, y and z directions).

Project 13. Design and Test a Tribometer

Advisor: Profs. G. Shiflett Difficulty: Moderate

A tribometer is a measurement device that

estimates the kinetic friction between two sliding

surfaces. One variation of a tribometer is the

pin-on-disk apparatus shown below. This

system presses a pin onto a rotating disc; the

load applied to the pin (onto the rotating surface)

in precisely known and the resultant force

applied to the mounting arm is measured to

reveal the kinetic friction of the system.

Design and construct a tribometer and

determine the kinetic coefficient of friction

between various materials. Some design

considerations include the applied load, rotation

rate, variations with temperature and contact

surface area.

(image from nanovea.com)

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Project 14. Tunable Shock and Vibration Test Device

Advisor: Profs. C. Radovich and V. Eliasson Difficulty: Easy to Moderate

Shock testing is commonly performed during the qualification phase of any structure that may experience an impact or rapid acceleration (e.g., a laptop case, spacecraft payload, etc.). This type of test is performed by striking the structure with large mass. For example, a swinging hammer can be supported above the structure and then released to provide a shock to the test subject. The strength of the impulse is measured by an accelerometer where, the amplitude is typically expressed as a multiple gravitational acceleration (gs).

When a structure is exposed to this type testing, it is usually tested at specific shock amplitudes corresponding to events or scenarios it is likely to experience. Examples include: a 1g shock test of a cargo box (to simulate an accidental drop) or, a 10g test to simulate an explosive bolt used during stage separation of a spacecraft. Therefore, it is desirable to have a tunable shock testing device that can provide particular amplitudes.

For this project, design a tunable shock testing device that can provide specific shock amplitudes to a test subject. One possible configuration is sketched below although better designs may exist. Some design considerations for the striking block may include the mass, the material and the velocity. Various plate materials could be used as well. Are there predictable relationships between the shock amplitude and the kinetic energy of the system? Is the system dependent on the materials of the two striking surfaces? The character of the pressure wave passing through the plate could also be measured. The control valve must be designed such that it does not restrict airflow when opened. Ear protection must be worn for all tests.

Project 15. Maximizing the Power Output of Solar Cells

Advisor: Prof. C. Radovich and Y. Staelens Difficulty: Easy to Moderate

The effectiveness of a solar cell at producing usable power is directly related to the amount of incoming

light (solar irradiance, W/m2). Unfortunately, the amount of available solar irradiance varies greatly with

geographic location and time of day. Therefore, given the expensive cost of solar cells, it is desirable to

maximize the amount of solar irradiance incident on any given solar cell (i.e., maximize the number of

Watts per m2).

Using an off the shelf solar cell, design and test various modifications that will augment the solar

irradiance received by the solar cell and measure how each variation affects the power output. Examples

include, but are not limited to: reflectors, incidence angle, sun tracking and/or lenses. An optimal setup

may be found using a combination of add on devices. Are there any limits associated any of these devices

(theoretical, practical, financial, etc.)?

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Project 16. Effect of Turbulence on Trichodesmium Nitrogen Fixation

Advisor: Prof. P. Ronney Difficulty: Difficult

Trichodesium is a family of marine bacteria that are responsible for a large portion of the conversion of

atmospheric nitrogen into organic nitrogen that is needed by all living organisms. The understanding of the

rates at which trichodesium convert ("fix") nitrogen is crucial to developing accurate models of the earth's

organic nitrogen balance; in fact, managing the nitrogen cycle is one of the 14 "Grand Challenges"

recommended by the U.S. National Academic of Engineering. One facet of trichodesium that has never

been characterized is the way in which turbulence in the ocean affects the formation of colonies (which are

an essential part of the trichodesmium life cycle). In this study, the effect of turbulence on colony

formation and nitrogen fixation will be studied using a Taylor-Couette cell which provides extremely well

controlled turbulent flow.

Project 17. Microscale Combustion


It is well known that the use of combustion processes for electrical power generation provides enormous

advantages over batteries in terms of energy storage per unit mass and in terms of power generation per

unit volume, even when the conversion efficiency in the combustion process from thermal energy to

electrical energy is taken into account. The objective of this project is to develop combustion-driven power

generation devices at very small scales, typically in applications where batteries are currently used.

Currently we are studying ways to minimize or prevent flame extinction in small-scale combustors, which is

more problematic than for large-scale combustors because of higher surface area to volume ratios for

small-scale combustor and thus larger heat losses. This project entails testing the performance of various

small-scale combustors and determining optimal operating conditions.

Project 18. Transient plasma ignition for small internal combustion engines


Transient plasma ignition is a potentially attractive technology for the ignition of small internal combustion engines because of engine data showing significant reductions in ignition delayignition of leaner fuel-air mixtures, lower specific fuel consumption, and a faster ignition process. Such a faster

process will reduce thermal losses, and thus is potentially enabling for long-distance small engines with large area to volume ratios. Students would conduct build an apparatus and conduct experiments to increase understanding of the mechanism for transient plasma ignition as applied to small engines such as the 2 hp Fuji Imvac BF-34EI, and to optimize the effectiveness of transient plasma ignition systems.

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Project 19. What is the Drag of an Ammonoid?

Advisor: Profs. Spedding and C. Radovich Difficulty: Moderate

Ammonoids are interesting beasts that have been very successful over geological time scales. They live immersed in sea water and look like flattened sea shells. When they swim they go at about -- well no-one really knows, but maybe around . A typical streamwise length scale might be and so is about . Jacobs (1992) has measured drag on a number of different ammonoid bodies, but the drag measurements are poorly done and not understood. There is no proposal of why the drag might (or might not) vary with flow speed ( ), and the description of the origin of drag is, let us say, of uneven quality.

So, an interesting project may be to measure the drag on ammonoid-shapes bodies, combined with dye visualization experiments. This way, the measured forces can be explained in terms of the flow field.

A successful project would involve: figuring out what ammonoids are, and what kind of shapes they have; finding out how an ammonoid swims, and at what typical speeds, orientations and propulsion mechanisms; researching fluid mechanics lecture notes and standard texts for proper, consistent definitions or drag and its physical origin; selection of a series of shapes, surface textures to test in a water channel experiment; accurate measurement of drag at selected Re, for selected families of shapes; comparisons with Jacobs (1992) paper, with reasons for similarities and differences.

References: David Jacobs. Shape, drag and power in ammonoid swimming. Paleobiology, 18(2), 1992, pp. 203-220.

Klug, C. and Korn, D. The origin of ammonoid locomotion. Acta Palaeontologica Polonica 49(2), 2004,

pp. 235-242.

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Project 20. Is Low Reynolds Number Flow Over a 2D Airfoil Geometry Two Dimensional?

Advisor: Prof. Spedding Difficulty: Moderate to Difficult

The development of practical flying devices with wing spans on the order of 30 cm and flight speeds around 10 m/s brings the wing section characteristics into a Reynolds number domain (104 Re 105) where small changes (in geometry, freestream turbulence) can have very large effects. Surprisingly, there is much disagreement and confusion in the literature about how, and whether flow separation takes place, and whether this process is two-dimensional or not (e.g. El07, Al00).

At USC, we have been studying the behavior of fixed airfoils, focussing on the Eppler 387 (e.g. Sp10). This choice of airfoil section geometry was one where mean lift and drag coefficients have been shown to vary greatly with small changes in angle of attack. The tests thus far have been in the Dryden wind tunnel, and current work is being supported by the US Air Force.

As a companion experiment to existing wind tunnel work, we would like to answer for ourselves whether the flow over a 2D wing is itself 2D, and whether flow features observed in 2D geometries are the same, or different, depending on wing aspect ratio, with confined or free ends.

The experiment would involve building a model of the E387 airfoil/wing, with embedded lines for dye visualisation. Dye would be used to document the flow, in pictures taken from the side and from above the airfoil/wing. We will set the initial Reynolds number to 60,000. The spacing between separation and wake vortices would be used as a measure of the most important instability (Ya09).

The steps involved in the project would be:

1. Read provided literature references. Discuss with Prof.

2. Investigate Blue Water Channel (BWC) in AME Dept. Find wing and airfoil geometries that will

provide the required Reynolds number.

3. Design a series of studies and timeline. Propose how images will be (a) gathered; (b) analysed.

4. Construct 3D printer model that has embedded dye lines. Finish surface so it is smooth.

5. Run experiments, etc etc.

References

[Al00]" Alam M and Sandham ND 2000 Direct numerical simulation of short laminar separation bubbles with turbulent reattachment. J. Fluid Mech. 410, 1-28.

[El07]" Elimelech Y, Arieli R and Iosilevski G 2007 Flow over NACA-0009 and Eppler-61 airfoils at Reynolds numbers 5000 to 60,000. AIAA J. 45, 2414-2421.

[Sp10]"Spedding GR and McArthur J 2010 Span efficiencies of wings at low Reynolds numbers. J. Aircraft 47, 120-128.

[Ya09]"Yarusevych S, Sullivan PE and Kawall JG 2009 On vortex shedding from an airfoil in low-Reynolds-number flows. J. Fluid Mech. 632, 245-271.

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Project 21. Numerical Optimization and Wind Tunnel Testing


Project 21A: Airfoil Optimization

Numerical airfoil analysis techniques can be combined with numerical optimizers to quickly analyze a large number of airfoil shapes and find airfoils that maximize/minimize a certain metric subject to certain constraints. More specifically, MATLAB has a number of optimization packages that can be implemented on the airfoil analysis of Xfoil, a numerical airfoil analysis tool. This has been done by Byron Young from UC Boulder, and this method will be the subject of this project. The students will be expected to learn the methods, and produce their own optimized airfoil (the definition of optimized is up to the students to decide). This airfoil, along with other hand-designed high performing airfoils as well as other numerically optimized airfoils, will be tested in the AME Lab wind tunnel. Lift and drag will be measured for each airfoil

at a range of angles of attack and values of Re. It is expected that multiple airfoils will be tested and compared to the numerical analysis results. The wind tunnel measurement system is already in place, and Xfoil can be learned very quickly, so the challenges of this project will be to learn the optimization method(s) and to construct the airfoils. The author of the optimization code is available for assistance, and

might be available for a campus visit. The construction technique could be CNC hot-wire out of foam, or CNC mill out of aluminum, or 3D printed, etc. All of these techniques are well understood by the advisors.

Numerical airfoil analysis codes often converge on strange solutions for a given airfoil shape. Sometimes, these strange solutions are real, and sometimes they are not. Thus, an optimizer that is built on these analysis codes can often find strange airfoil shapes that numerically perform very well, maybe 20-30% higher L/D. One question of this project is to determine if these strange shapes are taking advantage of real physics (like separation bubbles and reverse flow) to get these results, or if it is simply a numerical fallacy. If it is later, it would be nice to identify these deficiencies and modify the optimizer or the analysis code to ensure that we do not end up with bad numerical results.

References Abdurrahman Hacioglu, Fast Evolutionary Algorithm for Airfoil Design via Neural Network, Volume 45, Number 9, Sept 2007, page 2196.

AIAA Journal, Volume 23, Number 5, May 1986, page 355.

Project 21B: Propeller Optimization

Similar to the above project, numerical analysis of propellers can be combined with a variety of optimization techniques to yield high performance propellers. However, some of the results seem strange

compared to conventional propeller design, and it is not clear if the numerical results are real. Wind tunnel testing for this project will require some modifications to the measurement setup in the wind tunnel. The construction technique could be 3D printing or CNC machining, and motors will need to be purchased for testing.

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Project 22a. Fire/Pollutant Spread in a Building

Advisor: Prof. Y. Staelens Difficulty: Easy to Moderate

There have been a number attempts to try to understand fire-spread in buildings using laboratory

models. One of the more interesting concerns is the rate of rise of hot products in a vertical duct; e.g., a

stairwell or elevator shaft. Here a vertical tube containing dense salt water was placed in a tank of fresh

water and the rise of the interface is measured (see Fig. 1). In this case the bottom of the tube was open.

The question arises: How is the rate of rise changed if

the exit is partially blocked (e.g., by the partially open

doors of an elevator shaft)?.

Set up an experiment to check this effect. For example,

Figs. 2 show three possible arrangements that should be

tried in order.

Reference: E. Zukoski, A review of flows driven by natural convection in adiabatic shaft, Caltech, Pasadena, October 1995.

iFigure 1 - Possible experimental setup

Figure 2 - Different configurations to be studied

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Project 22b. Fire Spread in a Stairway


The aim is similar to that of Project 22a, except the interest is in fire spread in an inclined tube as

shown in Fig. 3 (a staircase, for example). Determine how fast the low/high density fluid rises/falls in the

tube as a function of the density difference and tube angle. Divide the velocity by the characteristic velocity

calculated from the independent variables. How does this dimensionless velocity vary with the inclination

angle, ? Clearly, as the angle approaches a right-angle you should recover the results of Project 22a.

Figure 3 - Inclined duct setup

Project 23. Aerodynamics of a Flag

Advisor: Profs. C. Radovich and Y. Staelens Difficulty: Moderate

This project involves the measurement of the drag coefficient of a flag, plus the frequency and wavelength of the flapping dynamics. The objective is to characterize the functional dependence of these quantities in terms of relevant non-dimensional parameters. The project requires careful choice of different flag materials, the construction of a mount for placement in a wind tunnel (i.e., one which allows accurate measurement of the drag force of the flag), and consideration of a means for measuring the frequency and wave length of the flapping motion. Some possibilities for exploration include the testing of flags having a range of fabric densities, shapes, aspect ratios or perhaps porosity. If possible, some consideration of one or two materials that allow evaluation of the effect of flag stiffness (or resistance to flapping) could also be considered.

Reference: S. Taneda, Waving Motions of Flags. J. Phys. Soc. Of Japan, Vol. 24, No. 2, February 1968.

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Project 24. Wind Energy - Design and Analysis of Microturbnes

Advisor: Prof. S. Nutt Difficulty: Moderate

A presently untapped source of wind energy is generated by vehicular traffic. A plausible approach for harvesting this energy involves the design and installation of micro-turbines along highway medians, as illustrated below.

Evaluate generator efficiencies for different wind speeds for a prototype vertical wind turbine. Measure voltage and current for different wind speeds using prototype blades and generators. Analyze cost/benefits for select materials and manufacturing processes amenable to producing fan blades from composite materials.

Project 25. Four Axis CNC Hot-Wire Foam Cutter

Advisor: Prof. C. Radovich Difficulty: Difficult

Last semester, a four axis CNC hot-wire foam cutter was designed, constructed and almost put into service. Once complete, the device will be capable of producing precisely cut foam shapes such as airfoils for model airplanes or high quality wind tunnel models of (almost) any profile. However, the ultimate product desired from this device is the ability to cut tapered wing sections. Given the nature of hot-wire cutting, carving a tapered wing requires careful thought about how to address each end of the wing section. Since the perimeters at each end are different, the speed of the cut, heat setting and distance from the desired final surface need to be considered.

This project entails finalizing the construction of the CNC hot-wire apparatus, programming the stepper motor control routine and calibrating the device for at least one grade of high density foam. A tensioning device will likely be needed to accommodate the wire length required for making tapered cuts.

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Project 26. Drag Reduction and Fuel Savings for Commercial Trucks

Advisor: Prof. C. Radovich Difficulty: Moderate

Over the past thirty years, there has been a great deal of research regarding how to reduce the aerodynamic drag on a commercial truck. This is no surprise considering a single truck may travel over 160,000 km annually and fuel consumption has a direct impact on the bottom line. As a result of extensive wind tunnel and road testing, the testing community has recommended various add-on devices including an aero fairing on the main cab, cab extenders, base flaps and trailer skirts. Until recently, only the aero fairing and cab extenders were commonplace; however, with the ever increasing price of fuel, truck and fleet owners seem more willing to implement additional fuel saving measures. In particular, there seems to be an aggressive trend to add trailer skirts, as shown in Figure 1.

This objective of the project is to investigate one or more commercially available add-on devices for a commercial truck. The experiment will be conducted in the AME Lab wind tunnel using a truck model constructed out of high density foam (or another suitable means). For a given device, various geometries or profiles could be tested, or the angle of incidence/attachment could be investigated. Drag can be measured using the available force balance although a mounted fixture (integrated into your model) must be designed. What is the measured drag increase/decrease vs. Reynolds number? How do these results vary with yaw angle? The manufacturers of these devices often claim a specific fuel savings percentage;

e.g., Freight Wing claims a proven 7% fuel savings through the use of their Aeroflex trailer skirt. How do the quoted numbers compare with your wind tunnel test results? How far must a truck travel before recouping the initial cost of the device?

References J. Leuschen and K. Cooper, Full-Scale Wind Tunnel Tests of Production and Prototype, Second-Generation Aerodynamic Drag-

Reducing Devices for Tractor-Trailers, SAE 06CV-222.

S. Watkins, J.W. Saunders and P.H. Hoffman, Comparison of Road and Wind-Tunnel Drag Reductions for Commercial

Vehicles, J. Wing Engineering and Industrial Aerodynamics, 49 (1993) 411-420.

F. Browand, C. Radovich and M. Boivin, Fuel Savings by Means of Flaps Attached to the Base of a Trailer, SAE 2005-01-1016.

K. Cooper, The Effect of Front-Edge Rounding and Rear-Edge Drag of Bluff Vehicles in Ground Proximity, SAE 850285, 1985.

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Project 27. Propeller Static vs. Dynamic Thrust Measurements


A simple way to quantify the performance of a propeller is through static thrust testing. This entails mounting a load cell to an electric motor and propeller assembly, then measuring the induced thrust as a function of throttle setting, RPM, power draw, advance ratio, etc. However, this may or may not produce accurate performance characteristics since pulling air through the propeller (statically) could produce conditions different from that experienced in free flight. Thus, dynamic thrust measurements (i.e., in a wind tunnel) are often preferred.

This project will require a thrust stand to be built and used to acquire static and dynamic thrust measurements. Dynamic thrust will be measured in the AME Lab wind tunnel. An interesting investigation might be to quantify the sensitivity of the dynamic thrust measurements to the simulated flight

environment (i.e., the wind tunnel speed). Consider a given propeller at a fixed throttle setting: what happens to the measured response if the freestream velocity is higher or lower (e.g., +/-10%, 20%, etc.) than the design flight speed? Are the results still useful? Can a predictable correction be applied to the measured results? Another experiment could focus on the effects that clipping the tips of a prop (i.e.,

shortening the radius) has on performance. Straight, rounded or other? Is there an optimum profile for trimming a prop?

References R. Deters and M. Selig, Static Testing of Micro Propellers, 26

th AIAA Applied Aerodynamics Conf., AIAA 2008-6246.

J. Brandt and M. Selig, Propeller Performance Data at Low Reynolds Numbers, 49th

AIAA Aerospace Sciences Meeting,

AIAA 2011-1255.

M. Selig and G. Ananda, Low Reynolds Number Propeller Performance Data: Wind Tunnel Corrections for Motor Fixture

Drag, UIUC internal document (http://www.ae.illinois.edu/m-selig/).

Project 28. Air Intake Fairing of a Radio Controlled Sport Jet Airplane

Advisor: Prof. Y. Staelens and E. Schuster Difficulty: Moderate to Difficult

Mr. Ewald Schuster, a research laboratory technician in the AME department, is a well-known movie

set and model airplane builder. One of his latest endeavors is to build the fastest radio-controlled electrical

airplane possible. To do so Mr. Schuster needs you to design and build a fan fairing that would optimize lift

and thrust output of an existing electrical RC-airplane he is planning on using for his speed conquest. The

project consists of the following tasks:

Build a CAD model of the existing electrical airplane using SolidWorks or SolidEdge.

Design the fan fairing and integrate it on the airplane model.

Perform some CFD analysis on the designed fairing.

Optimize the design for lift and thrust output.

Build a scaled model for wind tunnel testing.

Verify the CFD optimization and results with wind tunnel data.

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Project 29. Rolling Resistance of a Golf Ball The Speed of a Green


One who watches golf matches on TV is made constantly aware of the speed of the greens. Greens are either fast, or extremely fast, or slow, etc. The speed of a golf ball on a green depends upon many things, including: the slope of the green, the length and type of grass, which way the grass is growing (grain), how the ball is struck, etc. As far as I know, there is no objective and quantitative means to determine the speed of a green. The task will be to decide upon a quantitative measure such as the rolling resistance of a golf ball and devise a means for consistently evaluating this measure. To verify the results, one could gather statistics on green speeds for a number of golf courses in the area.

Project 30. The Swing of a Baseball Bat


Baseball players are often obsessed with understanding their swing mechanics in order to maximize

power or direct a ball into precise locations of the playing field. A hitter can improve their swinging power by increasing the bat speed at the contact point. This is accomplished by synching the motion of their legs, hips, torso and arms to provide the strongest swing. However, precise control over the location that a ball is hit comes from subtle adjustments in the hitters posture, body mechanics and angle at which contact is made.

Your customer (a baseball player) would like to know how subtle adjustments to their body mechanics would affect their resultant swing. This project entails the construction of an apparatus that can track the trajectory of a baseball bat and an analysis routine that can estimate the bat speed and angle at the point of contact. One possible means for doing this would be with an array of laser/light modules and photodetectors. How this device could be used effectively/efficiently should be given some thought; e.g., how long must one wait to see the results, then make an adjustment and swing again?

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Project 31. Mechanical Properties of 3D-printer material


Not long ago the AME 341/441 lab acquired a 3D-printer from Z-corp. It was purchased to facilitate the

building of complicated parts needed for senior projects. Unfortunately due to the lack of information on

the mechanical properties of the material used and the effect of the finish on them, multiple parts have

failed during testing. Therefore parts created with the 3D-printer have been reduced, as of now, to create

molds only.

The suggested project is to determine and tabulate the mechanical properties (tensile strength,

compression strength, Young modulus, etc.) of the material used in our 3D printer as well as the effects the

different finishing techniques employed have on these mechanical properties. The results will be used for

future senior projects during part designs.

Project 32. Instructional setup to demonstrate the difference between laminar and turbulent flow


Grasping the difference between a laminar and turbulent flow for an aerospace engineer working in fluid dynamics is crucial for solving problems correctly. When first introduced to the concept one is usually confused since the independent fluid particles are difficult to distinguish and it is almost impossible to follow their actual trajectories unless some special visualization techniques are used. In the Webster dictionary one can find the following definitions for laminar and turbulent flow:

Laminar flow: the flow of a viscous fluid in which particles of the fluid move in parallel layers, each of which has a constant velocity but is in motion relative to its neighboring layers.

Turbulent flow: the flow of a fluid past an object such that the velocity at any fixed point in the fluid varies irregularly.

In other words a laminar flow is orderly and a turbulent flow is chaotic (see Fig.1).

The experiment consists in designing and building a portable setup so as to demonstrate the difference between a laminar and a turbulent flow to Aerospace and Mechanical engineering students when first introduced to this complicated and vital concept in the classroom (i.e., AME 105 and AME 341).

Figure 1 - Laminar and Turbulent flow in circular tube.

(http://www.ceb.cam.ac.uk/pages/hydrodynamic-voltammetry.html)

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Project 33. Instructional Setup to Demonstrate Reactions at Supports

Advisor: Profs. Y. Staelens and C. Radovich Difficulty: Easy to Moderate

Construct an instructional kit that can demonstrate the forces and moments that can be transmitted through various supports. One possibility is to make a threaded rod with a load cell (usually expensive) or several strain gauges instrumented at one end. Using the threaded end, the rod can be attached to various supports, and an LED display(s) can show the response for each F and M component when an external force is applied. In practice, it will likely be difficult (or impossible) for the user to apply forces exclusively along one component. Therefore, some thresholding circuitry and/or filtering might be required. An emphasis should be placed on packaging such that the instructional kit can be transported easily to a classroom and demonstrated to a class (e.g., AME 201). Consideration should also be given to the surfaces required.

Ref.: Beer and Johnston, Vector Mechanics for Engineers: Statics. Mc-Graw Hill.

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Project 34. Liquid Drops, Jets and Sheets

Advisor: Profs. T. Maxworthy and C. Radovich Difficulty: Moderate to Difficult

Project 34A. Fluid Rope-Coiling

This project focuses on the meandering or stitching patterns exhibited by a viscous fluid thread when deposited onto a moving surface. As observed by Lister, Chiu-Webster and several others, when a viscous thread falls onto a moving surface the fluid stream tends to coil or meander as shown below in Fig. 1. From these experiments, a variety of oscillatory modes dependent on the speed of the moving surface have been identified; however, many questions remain. How does the fluid stream behave when a subjected to a disturbance at the nozzle exit? Do vibrations on the moving surface augment the coiling mode in the same fashion? Does the roughness (or finish) of the moving surface affect the stitching pattern? Another interesting study would be on the behavior of non-Newtonian fluids or what happens when surfactants are introduced to the fluid.

A possible arrangement for the experimental setup is depicted in Fig. 2. A means for providing a constant flow rate of the viscous fluid, and a moving surface with a controllable/variable velocity needs to be constructed. References are provided on the following page.

Fig. 1. Stitching modes produced by a viscous thread Fig. 2. Possible arrangement for the experiment

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Project 34B. What Jackson Pollock Would Have Liked to Know Difficulty: Moderate

Jackson Pollock was an American painter that gained notoriety for his abstract artistic expressions and avoidance of convention. One of his techniques was to soak a paint brush (or cloth) in paint, then let the paint flow from the brush and onto a canvas. The resultant strokes were dependent on the viscous nature of the fluid, the distance between the brush and the canvas and the motion of his arm. Regarding his technique, consider the following: given a volume of a known viscous fluid on a paint brush, what is the diameter of resultant fluid stream? How does the diameter change with time or distance from the brush? What length and for what duration does the stream remain intact? Furthermore, what size droplets are produced once dripping ensues?

A variety of materials and techniques could be employed to investigate the characteristics of Pollocks abstract technique. This may include fluids of varying viscosity (glycerin, oil, paint, etc.), brushes of various shapes, sizes or composition, or a simple hand towel. To measure the diameter, length, etc. of the fluid a digital camera could be used.

For both Project 34A and Project 34B, a viscometer and tensiometer are available in the lab if needed.

References:

A. Herczynski, et al. , Painting with jets, drops, and sheets. Physics Today, June 2011.

S. Morris, et al., Meandering instability of a viscous thread, Physical Review, E 77, 2008.

N. Ribe, et al., Stability of a dragged viscous thread: Onsete of stitching in a fluid-mechanical sewing machine, Physics of Fluids, 18, 2006.

S. Chiu-Webster and J. R. Lister, The fall of a viscous thread onto a moving surface: a fluid mechanical sewing machine, J. Fluid Mech., 569, pp. 89-111, 2006.

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Project 35. Externally Driven Rayleigh Instability

Advisors: D. Plocher and C. Radovich Difficulty: Moderate to Difficult

A cylinder of liquid is subject to capillary instabilities as described by Rayleigh (1878, 1945). That is, if we introduce some small radially symmetric disturbance (cf. Figure 1) along the length of the cylinder, that disturbance will be either unstable or neutrally stable depending on whether is larger or smaller, respectively, than the cylinders circumference. The unstable disturbance will grow until the cylinder pinches off. The neutrally stable disturbances remain at their initial amplitudes.

Figure 1. Geometry for Rayleigh instability.

In the tire spray lab, water is delivered to the tires as a very clean jeta cylinder of liquid. As such it is subject to the Rayleigh capillary instability. Figure 2 is a picture taken in the lab of the jet perturbed in the unstable range.

Figure 2. Plateau-Rayleigh capillary instability on a water jet.

There is some interest in effects of forcingintroducing disturbances to the system in a controlled manneron the tire spray and one suggested way to force the spray-producing flow is to introduce disturbances in the water jet supplying water to the tire patch; i.e., force the spray-producing flow by forcing the jet. Possibly the easiest way to force the jet would be acoustically, using the varying pressure generated by a loudspeaker to impose a disturbance.

The goal of this project then would be to develop a technique for acoustically forcing the water jet. It would require the design of a nozzle to fit an existing Plexiglas tank, designing a system and developing a technique for forcing the jet, and characterizing the response of the jet to various forcing. Of interest would be the jets response to forcing in both the stable and unstable ranges. Measurements could be made using a point-and-shoot camera. Once the system is operational, high speed video runs at several forcing conditions could be taken for presentation purposes.

Ref.: Rayleigh, Lord 1878 On the instability of jets. Proc. London Math. Soc. 10, 4-13. Rayleigh, Lord 1945 The Theory of Sound, Vol. II. Dover.

Perturbed jet, Uj = 3.5 m/sUj

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Nano/micro/meso-scale flow investigations

The following projects relate to the future development of micro-scale devices (or MEMS,

microelectromechanical systems). Due to facility availability and the purpose of the 441aL class, the current

goal is to design, manufacture, and test scaled-up meso-scale (mm or cm size) prototypes. Additional to the

meso-scale prototype, designs and simulations of micro-scale devices can be done using CoventorWare.

CoventorWare is the leading MEMS development software and 441aL students have the privilege of

accessing it. For students who are interested in microfluidic systems such as inkjet printer heads, micro

pumps, and micro valves, CoventorWare microfluidic modules have the ability of modeling and simulating

the fluid flows in micro-scale with the considerations of micro- and nano-scale fluidic effects. An example of

a micro-scale mixer is shown in the following figure to demonstrate changes of concentration along the

mixer. Details regarding CoventorWare can be found in http://www.coventor.com/coventorware.html.

Figure 1. Simulation of a micromixer using ConventorWare

The followings are a few suggested projects. Students are encouraged to develop the projects of their

interest that can be applied in micro/meso-scale flow investigations.

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A. Thermal Creep Flow Application

Thermal creep flows, a rarefied gas phenomenon, can be utilized in micro/meso-scale pumping

systems. The Knudsen Compressor, a micro/meso-scale gas pump driven by thermal creep flows, has been

investigated by Prof. Muntz and Dr. Han for the past few years. A schematic illustration of a Knudsen

Compressor stage is presented in Fig. 2. A single stage is defined as the combination of: a membrane,

which consists of a parallel array of small gas flow channels; and a hot-side connector section, which has an

appropriately larger single flow channel. The rarefied flow phenomenon of thermal creep (or thermal

transpiration) occurs inside the membrane channels due to the imposition of a temperature gradient across

the thermal creep membrane. The connector is used to return the gas to its original temperature, prior to

entering the next stage. More specifically, a pressure increase across the membrane is created by the

temperature gradient along the membrane channels walls, due to the thermal creep effect. The direction

of the thermal creep flows inside the membrane channels is from cold to hot, thus left to right in Fig. 2. A

return flow, caused by the induced pressure gradient, creates a flow from the hot end to the cold end of

the membrane (right to left in Fig. 2). The maximum up-flow (defined as flows from left to right)

corresponds to a pressure change approaching zero, or a zero net up-flow can be obtained, assuming a

closed system, in which case a maximum pressure increase is present. In general, a linear temperature

decrease is also imposed along the horizontal wall of the hot-side connector section. In normal Knudsen

Compressor operations, the flow in the connector section is defined to be in the continuum regime

(Kn

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Besides all the previous work, there are still many interesting applications and variations of the

Knudsen Compressor that can be investigated and they are presented in the following projects.

Project M 1. Micro/Meso-scale Pump for Air Electrodes that Limits the Exposure of the Air Electrode to

the Atmosphere for Use in Micro Fuel Cells

Advisor: Prof. Muntz Difficulty: Moderate

Some fuel cell technologies produce energy from oxygen in the air. Oxygen (cathode reactant) diffuses

directly into the fuel cell system from atmosphere. Drying out of the air electrode or absorbing water

moisture from the humid air can adversely influence the electrode's performance. A suitably designed

micro-pump/air electrode structure that limits the exposure of the air electrode to the atmosphere could

result in extended service life making this system more attractive for many general use applications.

Figure 4. Illustration of the proposed Knudsen Compressor

The basic pump proposed here is a single stage Knudsen Compressor to provide the required air mass

flow for the fuel cell air electrodes. The possible design is shown in Fig. 4. An aerogel membrane is

sandwiched in between two thermal guards. The hot thermal guard conducts heat to one side of the

aerogel surface while the cold thermal guard keeps the other side of the aerogel surface close to ambient

temperature. Air will be drawn from the air inlet through the membrane to the air electrodes once the heat

source is on. When sufficient volume of air has been drawn into the chamber, the heat source will be

turned off and the sealing valve will be activated to seal the air inlet by simple electrical switches.

The task is to design and test the Knudsen Compressor to meet the required flow rate of 17 cc/min and

maximum power consumption of 6.5 mW/cc/min by choosing the heating method and the size of the

thermal creep membrane (aerogel is suggested here). The valve sys

ame 441al course handout - fall 2011

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