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July 29, 2015, 15:17 |
UDF for ball motion inside a valve.
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#1 |
New Member
Ahmed Jalal
Join Date: Mar 2015
Posts: 22
Rep Power: 11 |
Hello All,
I am trying to simulate motion of a ball in a valve. The model I created is a simple 2D half model of the cross-section of a hypothetical valve. There is an attachment of the model. I have created a UDF file to define motion of the ball due to velocity using the 6DOF solver. The symmetry line should also be deforming. I have a few questions. 1) Do I need to run a case without any Dynamic Mesh before compiling the code? 2) I keep getting an error that says: Unable to read motion history file 3) Can you please let me know if there are any suggestions to make to the UDF. Here is the UDF for the motion: #include "udf.h" DEFINE_SDOF_PROPERTIES(Lightweight_ball, prop, dt, time,dtime) { prop[SDOF_ZERO_TRANS_X]= TRUE; prop[SDOF_ZERO_TRANS_Z]= TRUE; prop[SDOF_ZERO_ROT_X]= TRUE; prop[SDOF_ZERO_ROT_Y]= TRUE; prop[SDOF_ZERO_ROT_Z]= TRUE; prop[SDOF_MASS] = 1e-3; prop[SDOF_IXX] = 1.92e-8; prop[SDOF_IYY] = 1.92e-8; prop[SDOF_IZZ] = 1.92e-8; } And someone suggested I do a changing time step UDF as well: #include "udf.h" #include "dx.h" #include "grid.h" #include "var.h" #include "mem.h" #include "dynamesh_tools.h" DEFINE_DELTAT(mydeltat,d) { int z_ID =5; real urf = 0.5; real mydx=1e-5; real maxT= 1e-3; real minT= 1e-10; real time_step; real my_vel; real TS1; Dynamic_Thread *ndt = NULL; Thread *ball_ft = Lookup_Thread(d,z_ID); ndt = THREAD_DT(ball_ft); my_vel = DT_VEL_CG(ndt)[1]; TS1 = ABS(urf*mydx/(my_vel+0.00000001)); //Message("\n My TS1 %f",TS1); time_step = MIN(TS1,maxT); //Message("\n My Time Step1 %f",time_step); time_step = MAX( time_step, minT); Message("\n My Time Step %f",time_step); return time_step; } |
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Tags |
6dof, dynamic meshing, mesh motion, remeshing |
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