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#1 |
New Member
Mohamed Magdy Mohamed
Join Date: Jan 2013
Posts: 9
Rep Power: 13 ![]() |
Hi,
I'm trying to simulate the movement of floating body in sea. I'm using a udf for wall movement : #include "udf.h" DEFINE_CG_MOTION(wave, dt, cg_vel, cg_omega, time, dtime) { cg_vel[0] = ((4)*(sin((63)*(time)))); cg_vel[1] = 0.0; cg_vel[2] = 0.0; cg_omega[0] = 0.0; cg_omega[1] = 0.0; cg_omega[2] = 0.0; } and another one for the floating body six_dof_property: /************************************************** ***** SDOF property compiled UDF with external forces/moments ************************************************** *****/ #include "udf.h" DEFINE_SDOF_PROPERTIES(sdof_properties, prop, dt, time, dtime) { prop[SDOF_MASS] = 85167.33; prop[SDOF_IXX] = 174112.84; prop[SDOF_IYY] = 28237716.54; prop[SDOF_IZZ] = 28237716.54; prop[SDOF_ZERO_TRANS_X] = TRUE; prop[SDOF_ZERO_TRANS_Y] = TRUE; prop[SDOF_ZERO_ROT_Z] = TRUE; printf ("\n updated 6DOF properties"); } when i check the "six DOF" option in dynamic mesh the wall doesn't move and this message appears: Unable to read motion history while if i unchecked it an error appears -but the waves are generated correctly-: incorrect cg motion UDF sdof_properties::libudf on zone 6 (assuming no motion) So if anyone could tell me whether I should -in my case- check the box beside "six DOF" in dynamic mesh options or not. knowing that :
Thanks. |
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#2 |
Senior Member
Paritosh Vasava
Join Date: Oct 2012
Location: Lappeenranta, Finland
Posts: 732
Rep Power: 23 ![]() |
Hello Again
I think that you must have something else in your UDF that describes the motion/position of other faces/boundaries in your domain. While you have moving/dynamic face/boundary the motion of mesh attached to this face affects the meshes attached to other faces/boundaries. I suggest you have a close look at the tutorial titled 'Using a UDF to Control the Dynamic Mesh of a Flexible Oscillating Membrane'. |
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