[Azi Lotfi]

Hi everyone

Does anyone here know how to write a udf for calculating time-averaged wall shear stress gradient (TAWSSG). I desperately looking for some help/hints on how to write a udf calculating it.

Any helps/suggestions on this would be much appreciated

cheers

[LuckyTran]

Do you mean the average of the wall shear stress gradient or the gradient of the time-averaged wall shear stresss (TAWSSG)? Meaning average first then gradient or gradient first and then average?

Activating the data sampling for time statistics will get you the time-averaged wall shear stress. Then you simply need to calculate its gradient. A post-processor would do this better than Fluent because Fluent is a solver not a post-processor. You need to define a discretization scheme for the wall shear stress. Tecplot or CFD-Post comes to mind.

[Azi Lotfi]

Hi LuckyTran,

I need to calculate two parameters: (i) the average of |WSSG| which means first calculating the magnitude of WSSG and then taking an average, (ii) the average of WSSG vector which means first finding the WSSG vector/matrix out of WSS and then taking a time-average.

I thought it would be much easier to write a udf for such calculations rather than post-processing. I've already done that for TAWSS, OSI and RRT but got stuck for WSSG sort of things.

Any suggestions on how to do this in post-processing/udf?

Many thanks

[Rupali]

Originally Posted by Azi Lotfi

Hi LuckyTran,

I need to calculate two parameters: (i) the average of |WSSG| which means first calculating the magnitude of WSSG and then taking an average, (ii) the average of WSSG vector which means first finding the WSSG vector/matrix out of WSS and then taking a time-average.

I thought it would be much easier to write a udf for such calculations rather than post-processing. I've already done that for TAWSS, OSI and RRT but got stuck for WSSG sort of things.

Any suggestions on how to do this in post-processing/udf?

Many thanks

Can you share with me how you calculated TAWSS, OSI and RRT?