Please check the following code
 

#include "udf.h" #define f 10.0 /*vibration frequency in Hz*****/ #define A 10.0 /*vibration amplitude in m/s^2*****/ #define pi 3.14 DEFINE_SOURCE (x_mom,c,thread,dS,eqn) { real source,t,xaccel; t=CURRENT_TIME; xaccel=A*sin(2*pi*f*t); source=xaccel*C_R(c,thread); dS[eqn]=xaccel; return source; } I need to know if the above code is correct, which desribes the inertial body force due to translational vibration applied in x-dirction. Thanks every body Nagi