[ssamton]

Hi there

i want to simulate like piston movement!

as shown in attached file, center line moves upward as time goes.

i used dynamic mesh(smoothing&remeshing).

so, center line moves well, but, does not working remesh function.

just move center line upward.

therefore, when center line arrive adjacent cell(i.e, adjacent upper cell), show error message: Negative cell volume.

please help me.

I'm just trying to studying dynamic mesh.

it's very simple problem, i think.

Ah, I also use UDF(CG_MOTION)

Thank you all.

Have nice day

[Amir]

Hi,

The best dynamic mesh technique for this purpose is "layaring". but if you insist on using smoothing, you have to enable it from TUI for all the cell types; additionally, I don't think that the quad elements can be remeshed.

Bests,

[ssamton]

Thanks Amir

i just want to simulate through any method.

first of all, i try to layering method

however, could you tell me more way to set up?

i read manual, but it's really hard to understand.

Thank you again.


below coding is mine and i hooked up only center line.





#include "udf.h"

DEFINE_CG_MOTION(butterfly_flex_UDF, dt, cg_vel, cg_omega, time, dtime)
{
cg_vel[0] = 0.0;
cg_vel[1] = 0.1;
cg_vel[2] = 0.0;

cg_omega[0] = 0.0;
cg_omega[1] = 0.0;
cg_omega[2] = 0.0;
}

[Amir]

Ok, your UDF looks fine. As I said the other methods aren't recommended in such movement. The onlt tip that you have to consider in layering method is just setting the cell height of each dynamic zones from mesh options tab.

Bests,

[-mAx-]

same topic here >> http://www.cfd-online.com/Forums/ans...ic-engine.html

[ssamton]

Thank you all^^

i solved this problem!!

thank you again!!