hello evry body I have Fluent 6.12.16. I have installed Basic C compiler the probleme is for dynamic mesch when i use

define---user-define -fuction-interpreted they work for other udf (profile velocity) but not for motion gird he make me error :

Warning: incorrect cg motion UDF benzamia on zone 3 (assuming no motion)

can any one help me please it's very urgently for me

------------- programme-----------------------

#include "udf.h"

DEFINE_CG_MOTION(benzamia, dt, vel, omega, time, dtime) {

/* reset velocities */ NV_S (vel, =, 0.0); NV_S (omega, =, 0.0);

if (time<0.1)

{

vel[0] = 0;

}

else

{

/* set x-component of velocity */

vel[0] = 0.1; vel[1] = 0;

}

}

why don't compile that? regards

can you help me i want to make move my cylinder in the middle of the fluid when download udf for dynamic mesh zone, fluent make me a warning: Warning: incorrect cg motion UDF mouvement on zone 4 (assuming no motion) zone 4 is my cylinder

what means this warning

thanks

Hi Benzamia,

I got the same problem than you.In fact, with a DEFINE_CG_MOTION, you have to compile it and not interprete it (it doesn't work otherwise). Be sure than your C compiler works well otherwise you will get the same problem. I suggest you Microsoft Visual C++ 6.0 (the official version; the free version doesn't work for this). Your UDF is correct, you don't need to put vel[1]=0, it's done by NV_S(vel,=,0.0).

Furthermore, I use an UDF quite similar to yours for a dynamic mesh but the mesh isn't updated and after a few iterations, I've got this message:

Mesh Statistics: Min Volume =-6.89746e-002 Max Volume =5.99320e+004 Warning: negative cell volume detected! Error: Update dynamic mesh failed! Error Object: ()

whereas I specified a dynamic mesh!! Any idea??