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-   -   Flat Plate Drag & Lift (http://www.cfd-online.com/Forums/main/15903-flat-plate-drag-lift.html)

 Joe October 20, 2008 10:19

Flat Plate Drag & Lift

Hi,

At very high angles of attack, airfoils are supposed to behave like flat plates. I suppose that the formulas for the lift and drag on a flat plate are fairly well to be approximated analytically, aren't they?

Does anyone know where I can find relations for drag and lift on a flat plate as a function of: - angle of attack - aspect ratio - Reynolds & Mach number ???

Thanks,

Joe

 Bikini Girl with Machinegun October 20, 2008 14:34

Re: Flat Plate Drag & Lift

It's not quite that simple.

As far as I know, there is only one "exact" solution, and that is for potential flow. For a flat circular disk, the lift slope coefficient is

C_L/AoA = 1.79002303

with a possible error in the last digit.

 Joe October 24, 2008 09:50

Re: Flat Plate Drag & Lift

Thanks

 Paul October 24, 2008 14:17

Re: Flat Plate Drag & Lift

Hi,

check "Fundamentals of Aerodynamics" by John D Anderson for some formulas for the flat plate.

You can also check the NACA report server for additional informations about the flat plate experiments and theory.

BTW the theory for flat plate works for potential flows (inviscid and irotational flows) and also for laminar flows (search for Blasius solution for the flat plate).

The flat plate in turbulent flow is not covered very well by the theory but I'm sure you can find a lot of empirical formulas.

Paul

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