# UDF Define grid motion and Remeshing dynamic mesh

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April 22, 2019, 04:38
UDF Define grid motion and Remeshing dynamic mesh
#1
New Member

nguyenhoa
Join Date: Apr 2019
Posts: 9
Rep Power: 6
Hi everybody
I am using the udf define grid motion to move the inlet boundary according to each time step (as picture shown). But during the process, the new grid is not added. I don't understand where the problem is, the wrong udf code or something else. Please help me
my udf code:
DEFINE_GRID_MOTION(girdmotion, domain, dt, time, dtime)
{
//Definitions of the Variables
face_t f;
Node *node_p;
real t = CURRENT_TIME;
real a;
int n;
//Position Update of node_p
begin_f_loop (f, tf)
{
f_node_loop (f, tf, n)
{
node_p = F_NODE (f, tf, n);
if (NODE_POS_NEED_UPDATE (node_p))
{
NODE_POS_UPDATED (node_p);
NODE_Y (node_p) = NODE_Y (node_p)+0.035*dtime;
NODE_X (node_p) = NODE_X (node_p)+0.035*dtime;
if (NODE_Y (node_p)>0.2009)
{
NODE_Y (node_p) = 0.2009;
}
if (NODE_X (node_p)>0.446)
{
NODE_X (node_p) = 0.446;
}
}
}
}
}
end_f_loop (f, tf);
}
Attached Images
 grid error.jpg (131.5 KB, 51 views) geometry.jpg (34.1 KB, 45 views) udf define grid motion.PNG (24.1 KB, 53 views)

 April 22, 2019, 21:36 #2 Senior Member   Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 33 what does your last (third) picture means? why do you have code in console? best regards

April 22, 2019, 22:07
#3
New Member

nguyenhoa
Join Date: Apr 2019
Posts: 9
Rep Power: 6
Quote:
 Originally Posted by AlexanderZ what does your last (third) picture means? why do you have code in console? best regards
That is the same code as the code on console. This code is used to move the inlet as shown in Figure 2.

best regards

 April 22, 2019, 22:51 #4 Senior Member   Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 33 why do you have code in console? how do you hook UDF? step by step best regards

April 22, 2019, 22:59
#5
New Member

nguyenhoa
Join Date: Apr 2019
Posts: 9
Rep Power: 6
Quote:
 Originally Posted by AlexanderZ why do you have code in console? how do you hook UDF? step by step best regards
sorry it is my bad, i forgot that i have written this code in console so i attacted the third image to show this code.
i compiled this udf in fluent, hook this udf in dynamic mesh/dynamic mesh zones/ user-define, and preview mesh motion i have recieved result like picture 2. in this picture, new grid was not created. I think the problem is in my code.

best regards

 July 20, 2023, 03:22 DEFINE_GRID_MOTION UDF code #6 New Member   Naren Join Date: Jul 2023 Posts: 4 Rep Power: 2 Hi Im also facing issues while interpreting the UDF code.. Im getting "parse error" for the line:Thread *tf = DT_THREAD(dt); I checked multiple times, but cant clear this error. pls share your views on it..Thanks in advance

 July 20, 2023, 03:41 #7 Senior Member   Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 33 compile code __________________ best regards ****************************** press LIKE if this message was helpful

 Tags define grid motion, fluent, udf