[zhu-jsut]

hello, everyone
I have a question about the dynamic mesh. The initial 2D mesh is very simple, two layers of 10mm height quad mesh. One edge moves with a velocity defined by UDF:

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

real time;
time = CURRENT_TIME;
if(time <= 320)
vel[0] = 0.0;
else if(time > 320 && time <= 480)
vel[0] = 0.000125;
else if(time > 480 && time <= 1000)
vel[0] = 0.0002;
else
vel[0] = 0.0;
}

As shown here, the velocity is 0 in the first 320 seconds, and then the edge starts to move. The dynamic mesh setting, preview mesh motion, every thing is OK. As shown in preview mesh motion, the mesh has two layers until 320s, and then the layering starts.

However, the initial mesh (from 0s to 320s) became 4 layers after the initialization and run calculation, as shown in the mesh animation. Still, the simulation results conform to the logic, and the layering starts just after 320s. And if I extend time steps, the number of grid layers continue to increase but keep unchanged from 0s to 320s.

So, if anyone has ever encountered this problem, please tell me the possible reasons.

[zhu-jsut]

[IMG][/IMG]

fig1.png.jpg

[AlexanderZ]

compile your code, so you will avoid such problems later

variable time is already defined as a parameter of function, you don;t nee to redefine it
remove

real time;
time = CURRENT_TIME;

[zhu-jsut]

Originally Posted by AlexanderZ

compile your code, so you will avoid such problems later

variable time is already defined as a parameter of function, you don;t nee to redefine it
remove

real time;
time = CURRENT_TIME;

Thanks for your kind reply. I have solved this problem. it is caused by a misoperation. I always conduct preview mesh motion before initialization.

It is my first post on this forum. thanks again