Macro for wall shear stress gradient

Vitaly · February 23, 2012, 11:11

Hello,

I am writing a UDF to obtain the wall shear stress gradient.

If I have a WSS on a single face, I have an algorithm for finding the gradient based on the WSS of the surrounding faces.

Is there a macro to automatically identify surrounding faces?
Thanks,
Vitaly

dfytanid · February 28, 2012, 08:19

Hello Vitaly!

A good idea would be to store Wall Shear Stress (WSS) Values in UDS and after that use UDSI_G in order to access WSS gradient values.

Good work!

Vitaly · February 28, 2012, 10:13

Hello,

I am not sure how to get the WSS values. Do I have to calculate them or does Fluent allow me to just access them like I can access temperature values using F_T(f,t)?

I am getting confused by the macros in Fluent because some of them are not listed in the (very long) manual. Examples in the manual use macros that are never explained or defined (e.g. SV_UDS_I...what is that???). Is there a location where all these little things are explained?

It would be nice if there was an extensive list of macros and descriptions.

The ANSYS documentation is completely amateurish!!!

Thanks,

Vitaly

Azi Lotfi · April 2, 2018, 23:11

Hi

Does anyone here know how to write a udf to calculate time-averaged wall shear stress gradient (TAWSSG)?

Any suggestions would be much appreciated

cheers

gearboy · April 10, 2018, 03:55

Quote:

Originally Posted by Vitaly

Hello,

I am writing a UDF to obtain the wall shear stress gradient.

If I have a WSS on a single face, I have an algorithm for finding the gradient based on the WSS of the surrounding faces.

Is there a macro to automatically identify surrounding faces?
Thanks,
Vitaly

You can use the below macro to get the shear force on wall.

NV_VS(shear_force,=,F_STORAGE_R_N3V(f,tf,SV_WALL_S HEAR),*,-1); //F_STORAGE_R_N3V(f,tf,SV_WALL_SHEAR) is the fluid's force, so multiply -1 to get force on wall

February 23, 2012, 11:11	Macro for wall shear stress gradient	#1
Vitaly Member Vitaly Join Date: Jan 2012 Posts: 32 Rep Power: 14	Hello, I am writing a UDF to obtain the wall shear stress gradient. If I have a WSS on a single face, I have an algorithm for finding the gradient based on the WSS of the surrounding faces. Is there a macro to automatically identify surrounding faces? Thanks, Vitaly

February 28, 2012, 10:13		#3
Vitaly Member Vitaly Join Date: Jan 2012 Posts: 32 Rep Power: 14	Hello, I am not sure how to get the WSS values. Do I have to calculate them or does Fluent allow me to just access them like I can access temperature values using F_T(f,t)? I am getting confused by the macros in Fluent because some of them are not listed in the (very long) manual. Examples in the manual use macros that are never explained or defined (e.g. SV_UDS_I...what is that???). Is there a location where all these little things are explained? It would be nice if there was an extensive list of macros and descriptions. The ANSYS documentation is completely amateurish!!! Thanks, Vitaly Last edited by Vitaly; February 28, 2012 at 17:51.

April 2, 2018, 23:11	time-averaged wall shear stress gradient (TAWSSG) udf	#4
Azi Lotfi New Member miss001 Join Date: Aug 2014 Posts: 5 Rep Power: 11	Hi Does anyone here know how to write a udf to calculate time-averaged wall shear stress gradient (TAWSSG)? Any suggestions would be much appreciated cheers

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February 28, 2012, 08:19		#2
dfytanid New Member Join Date: Jun 2009 Posts: 11 Rep Power: 16	Hello Vitaly! A good idea would be to store Wall Shear Stress (WSS) Values in UDS and after that use UDSI_G in order to access WSS gradient values. Good work!