Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 1

ADDITIONAL NOTES ON DRAG

2-D Flow Past an Aerofoil

dF : total force on surface element dA = b ds

dFP : pressure (normal) force; dFS : shear force dFD: drag ; dFL : lift

dFD = dFP cosθ + dFSsinθ dFL = dFP sinθ - dFScosθ

chord

span

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 2

Drag Coefficients for High Reynolds Number Flows

2-D Objects 3-D Objects

Reference: Gerhart, P.M. and Gross, R.J., Fundamentals of Fluid Mechanics, Addison Wesley (1985).

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 3

Drag Coefficients for Low Reynolds Number Flows

Instead, of CD, use the Viscous Drag Coefficient: (L is a reference length)

Note: At high Re, the drag force is proportional to . In contrast, at low Re, the drag force is proportional to .

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 4

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 5

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 6

Flow Visualization Past Circular Cylinders

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 7

Effect of Edge Shape on Critical Flow Regime

Effect of Surface Roughness on Critical Flow Regime

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 8

Why there are dimples on golf balls

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 9

Boundary Layer Tripping for Separation Control

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 10

Streamlining for Drag Reduction

World Solar Challenge (solar-powered racing car) : CD = 0.07

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 11

Drag Coefficient of Road Vehicles

Separation Regions on a Car

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 12

Flows about a Bluff and a Streamlined Car Model

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 13

Strouhal Number for Circular Cylinders

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 14

Strouhal Numbers for 2-D Objects

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 15

Flow Induced Vibrations (Tacoma Narrows Bridge)

Additional Notes on Drag - Professor S. Tavoularis - MCG3341 FLUID MECHANICS II - p. 16

Breaking Up Spanwise Vortices