[Gyros]

Hello everyone!

I'm new to OpenFOAM. I'm trying to calculate the gradient of the velocity in a simulation using simpleFoam with the command

postProcess -func "grad(U)"

, but I get the error message "Failed to store pointer: grad(U). Risk of memory leakage". I tried using

simpleFoam -postProcess -func "grad(U)"

or adding the line

functions
{
  #includeFunc grad(U)
}

to my controlDict, but I got the same error message. The same postprocessing command works if I switch to icoFoam. Searching online, I found that this might be a bug https://develop.openfoam.com/Develop.../-/issues/2735. Do you know how I can circumvent this problem? Are there other ways to calculate the gradient of the velocity in postprocessing? Thanks a lot. I'm using OpenFOAM version 2312.

[Nafiz375]

Hello Gyros,
Did you solve this issue?
I'm also facing a similar problem.

[Gyros]

Originally Posted by Nafiz375

Hello Gyros,
Did you solve this issue?
I'm also facing a similar problem.

Hello Nafiz375.
I didn't solve this problem, but I circumvented it by calculating the velocity gradient in my program using the code

volTensorField gradU = fvc::grad(U);

It is not calculated in postProcessing, but this approach solved the problem for me. I needed gradU as input for another file, so instead of using gradU directly, I used U as input and calculated gradU in the new file.
I hope this helps.

[Nafiz375]

Hello Gyros, thanks for your reply.

The above problem was solved. I just deleted some lines from system/fvSolution:

cache
{
    grad(U);
}

Best
Nafiz