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Posted: Fri May 31, 2019 7:15 pm
Hope you are well.
I would like to ask you how can I perform a time average of the wall shear stress on the vertical wall of a square cavity i.e from the tutorial examples. I know the tangential stress can be called from post_util.f90 and pass the information in the cs_user_extra_operations.f90 in order to print it in a file but I do not know how the indexing corresponds to each component.
Thank you in advance,
Posted: Mon Jun 03, 2019 12:36 pm
In the file ￼￼cs_user_extra_operations-global_efforts.f90 there is an exmple how to compute global efforts on a subset of faces. Did you check it?
Posted: Fri Jun 07, 2019 6:14 pm
Thanks for you reply. I will check it though I do not know how valid is that approach if you use standard k-epsilon.
Posted: Sat Jun 08, 2019 1:05 pm
The efforts in the "global_efforts" example are based on accessing precomputed efforts/stresses, that are computed based on the different term contributions during a time step, so it should be correct with any turbulent model.
Note that when computation of efforts/stresses is activated (for example when requesting their postprocessing output in the GUI), the corresponding values are stored in a field, and you can simply use the field with standard time moment definitions (in the user subroutines, as this may not be accessible yet for boundary time moments).
Posted: Tue Jun 11, 2019 7:08 pm
Thank you for your reply.
I thought of finding a way to call directly the friction velocities from clptur.f90 i.e rho uk*uk and compute the wall shear stress. I supposed this is from where the code compute the efforts.
Though, is it possible to make a call for the variable uk in that routine and print it out in cs_user_extra_operations.f90 or do I have to declare a user field in the cs_user_parameters.f90?