[LeftCoefficient]

Hi! I'm trying to define the motion of a thread with DEFINE_GRID_MOTION. The movement of the wall is sinusoidal, and this occurs around a point of equilibrium. Then I need to save de initial coordinates of my thread to use them en the loop in order to update the position of the wall correctly.

Could any one help me??

This is my UDF:

DEFINE_GRID_MOTION(Expansion, domain, dt, time, dtime)
{
Thread *tf = DT_THREAD((Dynamic_Thread *)dt);
face_t f;
Node *v;
real displ;
real NV_VEC(axis);
real NV_VEC(posinit);
real NV_VEC(posupdate);
real A[ND_ND]; /* face area normal vector */
real AMag; /* face area magnitude */
int n;

SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf));

begin_f_loop(f, tf)

{

f_node_loop(f,tf,n)
{

F_AREA(A,f,tf); /*A is a vector, f face index, t thread index */
AMag=NV_MAG(A); /* Face normal vector magnitude*/
A[0]=A[0]/AMag; /* Componente en X del vector unitario */
A[1]=A[1]/AMag; /* Componente en Y del vector unitario */
NV_D(axis, =, A[0], A[1]);

v=F_NODE(f,tf,n);

if (NODE_POS_NEED_UPDATE(v))
{
NODE_POS_UPDATED(v);
displ=0.001*cos(2*M_PI*freq*CURRENT_TIME);
NV_V_VS(NODE_COORD(v), =, posinit, +, axis,*,displ);
Message("\n");
Message("Posicion inicial del nodo %i: %g mm\n",n,NV_MAG(posinit)*1000);
}

}
Update_Face_Metrics(f, tf);
}
end_f_loop(f,tf);
}

In summary, I need to get "posinit" was constant in all the time steps

Thanks in advance!

[Kimtero]

so I'd like to ask you how to deal with this problem? I met a similar problem.thanks

[AlexanderZ]

Originally Posted by Kimtero

so I'd like to ask you how to deal with this problem? I met a similar problem.thanks

if you need help open new thread and explain in detail your problem, attach your code and compilation log