Calculate shear stress in a laminar fluid flow using simpleFoam
 

I'm trying to obtain the shear stress from a flow on a rectangular passage with a cylindrical obstacle in the middle. Something like that on the picture. I saw some people on other posts saying that you can use the command wallShearStress to do the trick, but every time I try, I receive a message telling that the command is not recognized. Now, I don't know if there were some changes in the newer versions, or maybe I have to import some wallShearStress file to the system folder first, but I can't figure it out.

I'm definitely an OpenFOAM newbie, so if I'm not giving enough information, please let me know.

post processing wss
 

Hello Diego,
did you try doing:

simpleFoam -postProcess -func wallShearStress

after running your case?

Thanks
 

Yes. I have already tried it after much more digging through some other threads and it worked out beautifully. But i still dont know if this is the right WSS, because i read somewhere that the one that is computed in openFOAM is the WSS written on kinematic pressure dimensions, that is, as if we were calculating the WSS using the kinematic viscosity instead of the dynamic one.

And besides, if someone have a tip on how to deal with .dat information, like ploting curves and this sort of stuff, i would be really grateful. As i already am actually, thanks.

Post processing / data plotting
 

You can use tools like gnu plot. One such example for monitoring residuals in combination with`foamMonitor`:
Monitoring residuals

Hey Diego,
did you try to use:


functions
{

#includeFunc wallShearStress}


in the controlDict?


Otherwise, just to do as test, you can try simpleFoam -postProcess -list and check if wallShearStress is present.


Otherwise, try to turbolent, also if should not be this one the problem.


Last, reinstall OpenFOAM.