Moving mesh on NEKRS

[chanleonzen]

Hello there,

I was wondering if there is a moving mesh example for NEKRS similar to mv_wall in NEK5000?
Thank you.

Kind regards,
Leon

[yslan]

There is
https://github.com/Nek5000/nekRS/tree/master/examples/mv_cyl
similar to
https://github.com/Nek5000/NekExamples/blob/master/mv_cyl/mv_cyl.usr

[chanleonzen]

Thanks Yu-Hsiang. That’s great. I must have missed this when I downloaded nekrs a while back. Kind regards, Leon

…

On 25 Mar 2022, at 3:49 pm, Yu-Hsiang Lan ***@***.***> wrote:  There is https://github.com/Nek5000/nekRS/tree/master/examples/mv_cyl similar to https://github.com/Nek5000/NekExamples/blob/master/mv_cyl/mv_cyl.usr — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.

[chanleonzen]

I have run the case and it works but I do not see the mesh deformation as the coordinates are only dumped in the 1st field file. I need to change
platform->options.setArgs("CHECKPOINT OUTPUT MESH", "FALSE");
in the source code. However, I was wondering if there is a switch in the .par file which I can use?
Thank you.

[stgeke]

There is a par key writeToFieldFile. Run nekrs --help par for more details.

[chanleonzen]

Thank you for the tips and advice.

[chanleonzen]

I am getting this error
detected par file errors:
unknown key: mesh::writetofieldfile

I ran nekrs --help par but did not find the "writeToFieldFile" key either. This is for v21.1. Have I done something silly?

[stgeke]

Sorry it's something we added recently. A preview of the next upcoming release is available in the next branch.

[chanleonzen]

All good. Looking forward to the upcoming release and appreciate your help and support.

[chanleonzen]

I've been trying to modify the mv_cyl example to suit my case but I am having a bit of difficulty. Firstly, the example uses the low Mach solver and I am trying to change it to incompressible flow. So I've removed

udf.properties = &uservp;
udf.sEqnSource = &userq;

lowMach::setup(nrs, P_GAMMA);
udf.div = &qtl;

from UDF_Setup and

userVpKernel lowMach

from UDF_LoadKernels but I am getting issues with solving for velocity and the simulations explodes. Eventually, I would like to setup a channel flow with moving walls.

Thank you