Dear all,

i'm working on a project, in which i have to use the value of wall shear stress (wss) in a UDF. The main problem is that i can not find the wss argument name. Could anyone tell me the name of this particular variable? Of course, i have already unsuccesfully check the User guide.

Thank in advance for your variable help.

Dimitrios K. Fytanidis

Hi Dimitrios,

with this command you can retrieve the wall shear stress of a certain face f, e.g. in a loop over all faces of a thread tf.

The result is a 3D-Vector (there should be one for 2D as well), here the components are stored separately:

F_x = F_STORAGE_R_N3V(f,tf,SV_WALL_SHEAR)[0]; F_y = F_STORAGE_R_N3V(f,tf,SV_WALL_SHEAR)[1]; F_z = F_STORAGE_R_N3V(f,tf,SV_WALL_SHEAR)[2];

Hope this helps,

Regards szz

Thank you szz, But could you please tell me if these are stresses or forces. I check them and i found really strange results. Generally, I need the value of the component of Wall Shear Stress. Thank you in advance for your variable help.

Dimitrios

Hi,

sorry, it's the forces of course.

Dividing by the area should be possible for both the overall force and the components.

F_AREA(A, f, tf); area = NV_MAG(A);

I have found that although the value is accurate one has to be careful about the sign of the shear forces.

Regards szz.

Thank you szz!!!

Your help was really as usefull as valiable!!!

Regards,

Dimitrios