Moving mesh not working on GPU solver

[Nathaniel]

Hi all, I've been playing around with the GPU solver and have been very impressed with performance I can achieve on a desktop computer with a 4070 super.

I have been running my fluids simulations that I normally run on a server on my local computer on my gpu. Everything has been working great in my workflow except the moving mesh part of my problem. I've now tried running both my original journal file which works fine on the cpu solver as well as setting up my study from scratch for moving mesh.

When I use the gui and use the preview mesh motion function the mesh does move. However, when I run the gpu solver the mesh does not move. When I run the cpu solver the mesh moves. 

If you have any ideas how to debug this please let me know.

The journal commands I use to set up the motion in my case are as follows:

I use the use the auto non-conformal mesh creation
run my steady initial condition
switch to transient solver
I define a named number of named expressions for the mesh rotatoin speed:
/define/named-expression/add alphaDot definition "omega*A*cos(omega*t)" quit
I setup the grid motion:
/define/boundary-conditions/set/fluid domain-rotating ()
mgrid-motion? y
mgrid-x-origin no "CG"
mgrid-ai no 1
mgrid-aj no 0
mgrid-ak no 0
mgrid-omega no "alphaDot"
quit

[Rob]

Not everything is available in the gpu solver, so check https://ansyshelp.ansys.com/public/account/secured?returnurl=/Views/Secured/corp/v251/en/flu_ug/flu_ug_sec_gpu_solver_supported_features.html   Mesh motion (sliding mesh) looks to be available but I'd not expect any CG reference in that case. Try with a constant speed too. 

[Nathaniel]

Thanks Rob, yep looks like only constants or input parameters can be used at this time.

Everything works if I manually copy over the initial speed and the rotation point.

It is a shame that its not available yet, the gpu solver is so much faster on a desktop gpu compared to a desktop cpu. I am a little suprised by the functionality that it lets you define or select named expressions and will start solving without throwing a warning or error. 

Thanks for the help!

[Rob]

There are one or two omissions in system warnings; read the updates for 25R2 when that comes out to see what's available there.