Parametric study - adjusting lift and drag direction vectors

clarice · April 25, 2019, 10:18

I'm modeling an airfoil at various angles of attack with a parametric study. The inlet velocity direction vector is the input parameters and the output parameters are drag and lift coefficients.
When I change the angle of the inlet velocity, I want to change the drag and lift coefficient direction vectors accordingly, but unfortunately I can't use parameters in Fluent to specify the new direction vectors.
Can anyone please suggest a workaround to this? Can a UDF accept a parameter value as input?

LuckyTran · April 25, 2019, 11:13

UDF's can access and look at parameters.

Monitors have to be redefined when you want to change the axis. Even if you could reference a parameter to do this (and I think you can use a parameter in the definition), you still need a line in your journal somewhere that defines the axis. Parameters work as an on-demand pass-by-value, not a one-time symbolic link or pass-by-reference where you can set-it-and-forget-it.

April 25, 2019, 10:18	Parametric study - adjusting lift and drag direction vectors	#1
clarice New Member Clarice du Plessis Join Date: Aug 2017 Location: Stellenbosch University Posts: 9 Rep Power: 8	I'm modeling an airfoil at various angles of attack with a parametric study. The inlet velocity direction vector is the input parameters and the output parameters are drag and lift coefficients. When I change the angle of the inlet velocity, I want to change the drag and lift coefficient direction vectors accordingly, but unfortunately I can't use parameters in Fluent to specify the new direction vectors. Can anyone please suggest a workaround to this? Can a UDF accept a parameter value as input?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Calculation of lift and drag coefficients on airfoil	CoolHersheys	OpenFOAM Post-Processing	5	September 27, 2021 06:04
direction vectors for lift and drag in fluent	nauman55	FLUENT	7	September 23, 2020 14:47
Mesh Grid Study - Result Tolerance - Lift, Drag, Moment.	Wingman	Main CFD Forum	4	November 14, 2016 16:50
direction vectors for lift and drag for 3d wing	nauman55	FLUENT	9	July 4, 2014 06:22
Changing inflow velocity direction deteriorates lift and drag	ziggo	FLUENT	3	July 24, 2013 08:39

April 25, 2019, 11:13		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,676 Rep Power: 66	UDF's can access and look at parameters. Monitors have to be redefined when you want to change the axis. Even if you could reference a parameter to do this (and I think you can use a parameter in the definition), you still need a line in your journal somewhere that defines the axis. Parameters work as an on-demand pass-by-value, not a one-time symbolic link or pass-by-reference where you can set-it-and-forget-it.