Retrieve lift coefficient to udf

vishnuambali@gmail.com · March 10, 2016, 09:58

Hi ,

I am writing a UDF for FLUENT to input a velocity which is proportional to Cl(lift coeff).Can you please tell me how to retrieve the value of Cl from solver to UDF?

duri · March 14, 2016, 14:20

you can't extract cl directly from fluent. Calculate Fx, Fy and rotate it with angle of attack to get lift and drag force. Then use reference value to get the lift coefficient. I think Fx and Fy are stored in some variable or some direct functions available but not sure which one. If you couldn't figure out direct way to get Fx and Fy. Integrate pressure and wall shear on the face along x and y area vectors.

March 10, 2016, 09:58	Retrieve lift coefficient to udf	#1
vishnuambali@gmail.com New Member VISHNU Join Date: Jan 2016 Posts: 13 Rep Power: 10	Hi , I am writing a UDF for FLUENT to input a velocity which is proportional to Cl(lift coeff).Can you please tell me how to retrieve the value of Cl from solver to UDF?

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March 14, 2016, 14:20		#2
duri Senior Member duri Join Date: May 2010 Posts: 245 Rep Power: 16	you can't extract cl directly from fluent. Calculate Fx, Fy and rotate it with angle of attack to get lift and drag force. Then use reference value to get the lift coefficient. I think Fx and Fy are stored in some variable or some direct functions available but not sure which one. If you couldn't figure out direct way to get Fx and Fy. Integrate pressure and wall shear on the face along x and y area vectors.