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-   -   udf dynamic mesh (http://www.cfd-online.com/Forums/fluent-udf/112870-udf-dynamic-mesh.html)

hillat February 6, 2013 16:49

udf dynamic mesh
 
I am trying to built a simple problem of dynamic mesh

the grid is a rectangle and I want the lower wall would behave like a wave, something like
y=0.5*sin(10*t)
when t is the time

I wrote the following code but when I put it in the dynamic mesh I don't see any change in the mesh while run the calculation


Code:


#include"udf.h"
DEFINE_GRID_MOTION(beam,domain,dt,time,dtime)
{
Thread *tf = DT_THREAD(dt);
face_t f;
Node *v;
real NV_VEC(omega), NV_VEC(axis), NV_VEC(dx);
real NV_VEC(origin), NV_VEC(rvec);
real sign;
int n;
/* set deforming flag on adjacent cell zone */
SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf));
sign = -5.0 * sin (26.178 * time);
Message (
"time = %f, omega = %f\n", time, sign);
NV_S(omega, =, 0.0);
NV_D(axis, =, 0.0, 1.0, 0.0);
NV_D(origin, =, 0.0, 0.0, 0.152);
begin_f_loop(f,tf)
{
f_node_loop(f,tf,n)
{
v = F_NODE(f,tf,n);
/* update node if x position is greater than 0.02
and that the current node has not been previously
visited when looping through previous faces */
if (NODE_X(v) > 0.020 && NODE_POS_NEED_UPDATE (v))
{
/* indicate that node position has been update
so that itís not updated more than once */
NODE_POS_UPDATED(v);
omega[2] = sign * pow (NODE_y(v)/0.230, 0.5);
NV_VV(rvec, =, NODE_COORD(v), -, origin);
NV_CROSS(dx, omega, rvec);
NV_S(dx, *=, dtime);
NV_V(NODE_COORD(v), +=, dx);
}
}
}
end_f_loop(f,tf);
}

thanks for the help
hilla

syavash February 10, 2013 20:00

Quote:

Originally Posted by hillat (Post 406409)
I am trying to built a simple problem of dynamic mesh

the grid is a rectangle and I want the lower wall would behave like a wave, something like
y=0.5*sin(10*t)
when t is the time

I wrote the following code but when I put it in the dynamic mesh I don't see any change in the mesh while run the calculation


Code:


#include"udf.h"
DEFINE_GRID_MOTION(beam,domain,dt,time,dtime)
{
Thread *tf = DT_THREAD(dt);
face_t f;
Node *v;
real NV_VEC(omega), NV_VEC(axis), NV_VEC(dx);
real NV_VEC(origin), NV_VEC(rvec);
real sign;
int n;
/* set deforming flag on adjacent cell zone */
SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf));
sign = -5.0 * sin (26.178 * time);
Message (
"time = %f, omega = %f\n", time, sign);
NV_S(omega, =, 0.0);
NV_D(axis, =, 0.0, 1.0, 0.0);
NV_D(origin, =, 0.0, 0.0, 0.152);
begin_f_loop(f,tf)
{
f_node_loop(f,tf,n)
{
v = F_NODE(f,tf,n);
/* update node if x position is greater than 0.02
and that the current node has not been previously
visited when looping through previous faces */
if (NODE_X(v) > 0.020 && NODE_POS_NEED_UPDATE (v))
{
/* indicate that node position has been update
so that itís not updated more than once */
NODE_POS_UPDATED(v);
omega[2] = sign * pow (NODE_y(v)/0.230, 0.5);
NV_VV(rvec, =, NODE_COORD(v), -, origin);
NV_CROSS(dx, omega, rvec);
NV_S(dx, *=, dtime);
NV_V(NODE_COORD(v), +=, dx);
}
}
}
end_f_loop(f,tf);
}

thanks for the help
hilla

Hi,

I can't see any motion specified to y coordinate like that you've stated earlier!! Try to clarify your exact motion for us at first step till we might be able to help you.

tnx


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