[Ursmooth]

Hello

How do you run Standard utilities in openFoam? I have created a flow over a cylinder and I want to find its separation point, this can be found when the gradient of the boundary layer is zero, and I therefore want to compute wallGradU, but how do you run wallGradU, I tried to type icoFoam -postProcess -func WallGradU, but got error message (see picture). Do you need to implement it as a function in controlDict? I also tried this but got a error message as well

[robob]

As you can see on the output (invalid arguments) icofoam has no option postprocess.
postprocess is an own openfoam utility.
See the tutorial https://cfd.direct/openfoam/user-gui...#x5-130002.1.4
and https://cfd.direct/openfoam/user-gui...31-2400006.2.3

[robob]

and if I type "wallGradU" into the console (it was an openFoam utility)
then the following output is printed:
wallGradU has been superseded by the postProcess utility:
postProcess -func 'grad(U)'

[Ursmooth]

Thank you for your help robob. The postProcess -func 'grad(U)' it worked for time step 0 but for timestep 1,2,3 and so forth, it coulndt find required field U.
The command postProcess -func 'components(U)' worked fine though. How do you create field U? Is this done in the fvSolution with a gradscheme in fvSchemes?

[robob]

Normally U is writtten to all timesteps. There is something wrong with your solver. What commands do you execute for your simulation?

[shrirang]

There is an option in controlDict about writing files every time step, you can check that for your case.

Shrirang

[Ursmooth]

Just icoFoam, but I found this thread How to get grad(p) in OpenFOAM and it seems to be a bug in openfoam 4.1. The same version I am using.

[robob]

Looks like an bug indeed, thanks for the notice. Maybe you should try with OpenFOAM 5?

[Ursmooth]

Yes I will try that, Thanks again for your help!