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peritalsis problem using DEFINE_GRID_MOTION

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Old   June 23, 2009, 13:28
Default peritalsis problem using DEFINE_GRID_MOTION
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hi all,
i am doing a sinusoidal peristalsis problem in which the radius of the wave is given by: R(x,t)=epsilon+(a/2)(1-cos(2*pi/lambda(x-ct) . the respective values are provided. the program is supposed to take time, and x as input.
i have used a cfd as follows:
#include "udf.h"
DEFINE_GRID_MOTION(peristalsis,domain,dt,time,dtim e)
Thread *tf = DT_THREAD(dt);
face_t f;
Node *v;
real NV_VEC(axis),NV_VEC(val);
real val1, val2;
int n;

/*** set deforming flag on adjacent zone ***/
/*NV_D(axis, =, 1.0, 0.0, 0.0);*/

if (NODE_X(v) > 0.000667 && NODE_POS_NEED_UPDATE (v))

val1= 1-(cos((2*3.14/0.1)*(NODE_X(v)-0.0002*time)));
val2= 0.001+((0.0004/2)*val1);
val[2] = val2;
NV_V(NODE_COORD(v), =, val);
/*NODE_Y(v) = val2;*/

i have used very small time steps, but it is still giving negative cell volume as an error at the very first step. kindly help me.
hoping for a reply.
thanx a lot
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Old   June 25, 2009, 07:49
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kindly help as i am eagerly waiting for it
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