Lift Coefficient in fluent (reference value)

tonytonygood · November 19, 2018, 06:57

For the fluent solver, it uses the force to deduce the coefficient, but what should be the Area i should set in reference value?

I am doing a car model, I get the downforce but the lift coefficient seems to be incorrect since i don't know the area (should I use surface area or cross sectional area?). is there any way to compute the coefficient directly?

Thank you!

LuckyTran · November 19, 2018, 08:57

The reference area is defined in the definition of lift coefficient. Depending on who you are, what day of the week it is, and what time of day it is, the reference area chosen can be anything. If you don't know what the reference area ought to be, then there's no meaning to lift coefficient and you should probably shouldn't be looking at the lift coefficient in the first place. Why isn't the lift force sufficient? Is there a need to examine the lift coefficient?

However, the reference area is often the frontal cross-sectional area (which has nothing to do with lift but this makes the lift and drag coefficients consistent). A better area is the planform area (again a projected area but viewed from above). Both are used. Normally it is a cross-sectional area and not an actual surface area.

November 19, 2018, 06:57	Lift Coefficient in fluent (reference value)	#1
tonytonygood New Member Yuk Tong Cheng Join Date: Oct 2018 Location: Hong Kong Posts: 2 Rep Power: 0	For the fluent solver, it uses the force to deduce the coefficient, but what should be the Area i should set in reference value? I am doing a car model, I get the downforce but the lift coefficient seems to be incorrect since i don't know the area (should I use surface area or cross sectional area?). is there any way to compute the coefficient directly? Thank you!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Running UDF with Supercomputer	roi247	FLUENT	4	October 15, 2015 14:41
drag and lift coefficient fluent	bia	FLUENT	10	October 22, 2014 04:40
Constant velocity of the material	Sas	CFX	15	July 13, 2010 09:56
G95 + CGNS	Bruno	Main CFD Forum	1	January 30, 2007 01:34
Building OpenFoAm on SGI Altix 64bits	anne	OpenFOAM Installation	8	June 15, 2006 10:27

November 19, 2018, 08:57		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,761 Rep Power: 66	The reference area is defined in the definition of lift coefficient. Depending on who you are, what day of the week it is, and what time of day it is, the reference area chosen can be anything. If you don't know what the reference area ought to be, then there's no meaning to lift coefficient and you should probably shouldn't be looking at the lift coefficient in the first place. Why isn't the lift force sufficient? Is there a need to examine the lift coefficient? However, the reference area is often the frontal cross-sectional area (which has nothing to do with lift but this makes the lift and drag coefficients consistent). A better area is the planform area (again a projected area but viewed from above). Both are used. Normally it is a cross-sectional area and not an actual surface area.