FLUENT 6 - Transient Velocity Profile for Moving Wall
How can I assign a transient velocity profile to a moving wall ?
The following UDF will perform the job :
Thread *thread = Lookup_Thread(domain, wall_id);
real current_time = RP_Get_Real("flow-time");
THREAD_VAR(thread).wall.translate_mag = 10 - (5*current_time);
Here, wall_id is the integer value (zone id), corresponding to the moving wall thread. It can be obtained from Define -> Boundary Condition Panel. In the current UDF, wall velocity is related linearly with the time to assign a value to the moving wall.
A few points about the UDF and its use :
1) The UDF uses a macro which directly assigns the velocity to the thread corresponding to the moving wall, instead of going to the GUI to use the value assigned by user. So this UDF will not update the changes in the boundary condition corresponding to moving wall. To see the updated values on the moving wall, one has to display contours of velocity on that wall with node values enable and global values disabled. The Min and Max values reported in the Contours panel will be the updated values of the velocity assigned to the moving wall.
2) The direction of the wall velocity has to be set by the user in the wall boundary condition panel.