[Entwistle]

Hi all;

I need to use a DEFINE_GRID_MOTION based on the magnitude of wall shear stress on the wall of my mesh. I tried the next code:

#include "udf.h"
#include "dynamesh_tools.h"
#include "mem.h"

DEFINE_GRID_MOTION(cambio_malla,domain,dt,time,dti me)
{
Thread *tf = DT_THREAD(dt);
face_t f;
Node *v;
real vel, tau, area, visc;
cell_t c0;
Thread *ct0;
real t11, t12, t13, t21, t22, t23, t31, t32, t33;
real T1, T2, T3, T;
real NV_VEC(dz);
real A[ND_ND];
int n;

SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf));
NV_S(dz,=,0); /*Init the deformation vector as a zero-vector*/
begin_f_loop(f,tf)
{
f_node_loop(f,tf,n)
{
v = F_NODE(f,tf,n); /*Coordinates of the nodes*/

F_AREA(A,f,tf); /*Area vector of the face, in order to use the vector A_j=A n_j*/

visc=C_MU_T(c0,ct0); /*Viscosity of the fluid*/

t11=visc*(C_DUDX(c0,ct0)); /*Definition of the components of the viscous stress tensor t_ij*/
t12=0.5*visc*(C_DUDY(c0,ct0)+C_DVDX(c0,ct0));
t13=0.5*visc*(C_DUDZ(c0,ct0)+C_DWDX(c0,ct0));
t21=0.5*visc*(C_DUDY(c0,ct0)+C_DVDX(c0,ct0));
t22=visc*(C_DVDY(c0,ct0));
t23=0.5*visc*(C_DVDZ(c0,ct0)+C_DWDY(c0,ct0));
t31=0.5*visc*(C_DUDZ(c0,ct0)+C_DWDX(c0,ct0));
t32=0.5*visc*(C_DVDZ(c0,ct0)+C_DWDY(c0,ct0));
t33=visc*(C_DWDZ(c0,ct0));

T1 = t11*A[0]+t12*A[1]+t13*A[2]; /*Definition of the components of the force as T_i = t_ij A_j*/
T2 = t21*A[0]+t22*A[1]+t23*A[2];
T3 = t31*A[0]+t32*A[1]+t33*A[2];

T = sqrt(pow(T1,2)+pow(T2,2)+pow(T3,2)); /*Magnitude of the force vector*/

area = sqrt(pow(A[0],2)+pow(A[1],2)+pow(A[2],2)); /*Magnitude of the area vector*/

tau = T/area; /*Magnitude of the wall shear stress*/

vel=0.0158*pow((3.584*tau-1),1.5); /*Correlation for velocity of deformation of the bed as a function of the wall shear stress*/

if (NODE_Z(v)<0.001 && NODE_POS_NEED_UPDATE(v)) /*Condition for the deformation of the bed*/
{
NODE_POS_UPDATED (v);
dz[2]=vel; /*The bed only moves in the Z direction, as a vertical movement*/
NV_S(dz,*=,dtime);
NV_V(NODE_COORD(v), -=,dz); /*New positions of the nodes*/
}
}
end_f_loop(f,tf);
}
}

However, when I compile the code, fluent sends two warnings:

Warning: c0 may be used uninitialized in this function.
Warning: ct0 may be used uninitialized in this function.

Finally, when I run the simulation, fluent shows the next errors:

NODE XX: Process YYYYYYY: Received signal SIGILL (XX is a number from 0 to 19, I am running the simulation on a 20-nodes linux machine, and YYYYYYY is the number of the process assigned to the node XX).

NODE 999999: Process ZZZZ: Received signal SIGILL (ZZZZ is another number, but I haven't the node 999999).

MPI Application rank 1 exited before MPI_Finalize() with status 2. The fluent process could not be started.

Someone, please, could help me?

Thanks a lot.

[Entwistle]

Anybody has any idea about that?