Learning Forum

[Lutz Rohlfing]

License: Student 2024 R1

Hello,

I want to simulate the interaction between two opposing rotor blades. I use a UDF to move the blade surfaces in my domain. I use dynamic meshing to remesh at every time step. If I run the simulation on the four maximum allowed CPU cores, Fluent randomly closes without an error message. The only thing I could find in the log file is:

Error [node 999999] [time 5/10/24 1:20:45] Abnormal Exit!

The simulation runs fine when only using one CPU core.

This is my UDF:

#include "udf.h"

static real omegaY=0.0;

DEFINE_CG_MOTION(box,dt,vel,omega,time,dtime)
{
    NV_S(vel, =, 0.0);
    NV_S(omega, =, 0.0);

    omegaY= -2.6915;
    omega[1]=omegaY;
}

Does anyone have an idea on how to fix this? This significantly prolongs my calculation time.

[Rajat Chaudhari]

Hi ,

I dont see any issue in UDF,can you please try using less number of cores instead of using full capacity of CPU once.

Thanks

Rajat

 

[Lutz Rohlfing]

 

Hi Rajat,

Thanks for your response. I don't exactly understand what you mean. When I run Fluent on four cores, it crashes; however, it works fine on one core. Should I test with other numbers of cores, like two or three?

Kind regards,

Lutz

[Rajat Chaudhari]

Yes can once try with 2 or 3 cores ?

[Lutz Rohlfing]

I will try this and come back when i tested it, thanks!

[Lutz Rohlfing]

Hi Rajat,

i tried out what you suggested, but i again encountered this crash. What else could be the reason?

Kind regards 

Lutz

[Rajat Chaudhari]

Hi Lutz

Is it happening for other dynamic mesh cases also when you run them in parallel mode ? or is it with this speific case only ?

And are you getting this error while running the case or at the time of loading UDF itself ?

 

Thanks

Rajat