Air foil, drag coefficient

April 14, 2004, 18:33

I am trying to model an airfoil using k-epsilion model (standard wall treatment). Inlet air velocity is 100 m/s with 12 degree angle of attack. I get unusually large values for drag and lift coefficients (approx. 6000). What am I doing wrong?

April 15, 2004, 01:21

Hi, as you know Cx = X/D, where D = 1/2*rho*U^2*A, rho - density, U - velocity, A - area, X - force. FLUENT uses values which are specified in FLUENT reference panel (in FLUENT menu: report->reference values) by default. I think you must set correct values for density, velocity and area there.

regards

April 16, 2004, 01:40

Thanks Dmitry.... that did the trick !!

April 14, 2004, 18:33	Air foil, drag coefficient	#1
Amit Guest Posts: n/a	I am trying to model an airfoil using k-epsilion model (standard wall treatment). Inlet air velocity is 100 m/s with 12 degree angle of attack. I get unusually large values for drag and lift coefficients (approx. 6000). What am I doing wrong?

April 15, 2004, 01:21	Re: Air foil, drag coefficient	#2
Dmitry Guest Posts: n/a	Hi, as you know Cx = X/D, where D = 1/2rhoU^2*A, rho - density, U - velocity, A - area, X - force. FLUENT uses values which are specified in FLUENT reference panel (in FLUENT menu: report->reference values) by default. I think you must set correct values for density, velocity and area there. regards

April 16, 2004, 01:40	Re: Air foil, drag coefficient	#3
Amit Guest Posts: n/a	Thanks Dmitry.... that did the trick !!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Drag Coefficient Convergence Problem	John	FLUENT	18	June 24, 2023 10:22
mass flow in is not equal to mass flow out	saii	CFX	12	March 19, 2018 06:21
Incorrect Drag and Drag Coefficient for flow over a cylinder	ozzythewise	Main CFD Forum	8	June 13, 2012 07:24
air bubble is disappear increasing time using vof	xujjun	CFX	9	June 9, 2009 08:59
Automotive test case	vinz	OpenFOAM Running, Solving & CFD	98	October 27, 2008 09:43