airfoil & wing structur analysis

Perfil aerodinámico y Análisis de estructura alar.

4B - Airfoil & Wing Structure Analysis

Experimental Concept o Increased Lift = Increased Drag – Find the optimal Lift – to – drag ratio o Find Stall angle

Test Model/Device o Wing Structure (Finite and Infinite (Constrained on both sides of wind tunnel)

What Concepts to Prove and test against o To check the optimal lift-to-drag ratio when the AOA is changed o Find the stall angle o To find out how the tip deflects for a finite wing and how it compares to standards,

theoretical data and software

Theoretical Concepts & How to model the theoretical o Structural Analysis (COMSOL Multiphysics ) – Design an airfoil, rib and spar structure,

model in software, apply loads and see how the wing deforms (This would need to be scaled down), Beam Load distribution, Shear and Moment

o Lift to Drag ratio due to change of AOA (XFOIL, XFLR5) – Simple Cl, Cd and pressure distribution plots for the basic airfoil can be produced from XFOIL, More complicated designs (3D) can be shown with XFLR5, this can be plotted with Matlab once you output the data to Notepad++

How to model the experimental o Work with Aero Design team to have the wing created with their laser cutter – We would

need to model out what we want and contact them o Wind Tunnel

http://www.rit.edu/~w-me/facilities/windtunnel.htm Closed Circuit, low speed, 4’x2’ test section Pressure transducers to find pressure distribution Infinite Wing – Basic Lift-to-drag ratio and basis of comparison Finite Wing – Tip deflection found in structure, strain in wing, lift-to-drag ratio

change due to circulation at the tip of the wing (Tip vorticity – Image attached at bottom)

Cantilevered Static Wing Basic Aerostructures problem with weights applied to find the tip

deflection, strain and model (Can be done by hand and with comsol to compare and see how good our model is made)

Background knowledge o Simple theoretical concepts analyzed in Aerodynamics & Aerostructures

Final Projects attached for reference Extensive COMSOL, XFOIL, Matlab knowledge (Peter)

Classes applicable o Fluid Mechanics, Transport Phenomena/Aerodynamics, Aerostructures

Resources: Teachers, websites, standards, books, prior work o Dr. Venkataraman o UIUC Airfoil Database - http://www.ae.illinois.edu/m-selig/ads/coord_database.html o Airfoil Tools - http://airfoiltools.com/

o Anatomy of a STOL aircraft - http://www.zenithair.com/stolch801/design/design.html o NACA Airfoils in Aerodynamics text and online o Attached Final Projects:

Diagrams o XFOIL OUTPUT & Placed into Matlab with edited Airfoil:

Airfoil Tools outputs MANY things for common airfoils including the graphs below, Cm/alpha, Cd/alpha for many Reynolds numbers which give max Cl/Cd at the given angle of attack:

V-n, Load, Shear and Bending Moment Diagrams (Matlab – analytical)

COMSOL Modeling

Wing Tip Vorticity

Wing Tip Vortex changes with tip design

PROS o LOTS OF DATABASES o Wind Tunnel is readily available o Lot of possibilities in testing (Lots of depth obtainable) o New areas to learn/explore

CONS o Knowledge base isn't equally spread across team members o Software & Model needs to be extremely accurate o VERY in depth o Limitations of speed in wind tunnel (is data useful) o Time constraint in build