Learning Forum

[yakazuka]

Hello!ni am simulating a drop box test into water and for considering the moviment of the box i am using a UDF file with dynamic mesh. In a first step i run the simulation just with the gravity force and it was ok, Although In order to apply a initial force to the box i considering a force in the Y direction, as described by the UDF. The problem is that the box does not move when i applied this type of UDF. n/************************************************** *****nSDOF property compiled UDF with external forces/momentsn************************************************** *****/n#include udf.hnn#define BMODULUS 2.5e9n#define rho_ref 1000.0nnDEFINE_SDOF_PROPERTIES(box, prop, dt, time, dtime)n{n prop[SDOF_MASS] = 666.66;n  prop[SDOF_IXX] = 129.6296;n  prop[SDOF_IYY] = 111.1111;n  prop[SDOF_IZZ] = 129.6296;nnprop[SDOF_ZERO_ROT_X] = TRUE;nprop[SDOF_ZERO_ROT_Y] = TRUE;nprop[SDOF_ZERO_ROT_Z] = TRUE;nprop[SDOF_ZERO_TRANS_X] = TRUE;nprop[SDOF_ZERO_TRANS_Y] = FALSE;nprop[SDOF_ZERO_TRANS_Z] = TRUE;nn if (time < 0.020)nt {nt prop[SDOF_LOAD_F_Y] = -49;nt }n elsent {nt prop[SDOF_LOAD_F_Y] = 0.0;nt }ntn}nCould you be so kind and tell me where i am wrong?nThanks for your time!n

[YasserSelima]

Doesn't move at all?? Or you can not see difference between the two cases??nThe force magnitude is less than 1% of the weight, So, it is expected that you don't see huge difference. n