Re: [sparta-users] Help

[Steve P. <sj...@gm...>]

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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>