Re: [sparta-users] Help

[WUYONGXIN <183...@16...>]

Dear  Steve   ,

Thank you very much for your response—it was incredibly helpful. I truly appreciate your time and assistance.

Best regards,













At 2026-01-23 06:55:07, "Steve Plimpton" <sj...@gm...> wrote:

What you are suggesting here would be a 3rd way to model a rotating system.
You can look at the fix field/grid or fix field/particle commands to see if a "field"
could be specified as a formula in a grid- or particle-style variables 
which has the centrifugal and/or Coriolis effects on particle motion which you mention.
I don't think conceptually that this would work, but I haven't thought about it before.


Maybe others have ideas.


Steve


On Thu, Jan 22, 2026 at 7:28 AM WUYONGXIN <183...@16...> wrote:

Dear Steve,


     If I want to simulate a stationary rotor (i.e., describing the entire system in a rotating reference frame while keeping the rotor itself fixed relative to the rotating coordinates), how should the centrifugal and Coriolis forces acting on the particles be correctly set in SPARTA?


    I would greatly appreciate your guidance on this. Any advice or suggestions you could provide would be immensely helpful to me.


    Thank you once again for your time and support.
    Best regards,











At 2026-01-20 15:05:06, "WUYONGXIN" <183...@16...> wrote:



Dear Steve,



Thank you for your prompt reply.


Regarding the rotation, I was referring to simulating rotating components (e.g., rotating walls or rotor) in my simulation. Specifically, I would like to know how to properly set up the rotation effects in SPARTA—whether it should be done through the rotate command in surf_collide or if there are other recommended methods. Any guidance or suggestions on this would be greatly appreciated.


Thank you for your time and assistance.
Best regards,



At 2026-01-19 23:38:20, "Steve Plimpton" <sj...@gm...> wrote:

Hi - it looks like the tools/grid_refine.py tool has not been updated to use the newer grid file format
used by the read_grid, write_grid, adapt_grid, and fix_adapt commands.


So we can update the python file to use the common format.


Re: rotation, I'm not sure what you mean.  Do you mean in the context of grid adaptation?
Or just to include rotation effects in collisions?


Steve


On Mon, Jan 19, 2026 at 2:50 AM WUYONGXIN <183...@16...> wrote:

Dear sparta：
     My name is Yongxin Wu, and I am a student from ‌Zhejiang University from China.


    When using the grid_refine function in SPARTA to mesh a 3D geometry, a mesh file in parents format is generated. This file cannot be read by the read_grid command. May I ask how to convert it into a cells format file that the program can use? Additionally, if I want to account for the rotational effect of the wall, should I use the rotate command in surf_collide?


    Thank you for your time.
    Best regards



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