Hi all, I am new to Fluent,i am solving unsteady stage,the inlet velocity is function of time. is it possible to write the following udf?

#include "udf.h" DEFINE_PROFILE(unsteady_velocity, thread, position) { face_t f; begin_f_loop(f, thread) { real t = RP_Get_Real("flow-time"); if (0<=t && t<=0.72) F_PROFILE(f, thread, position) = (-45.1407*t*t*t*t*t+ 47.2291*t*t*t*t + 11.42*t*t*t - 26.9213*t*t + 8.1241*t + 0.9117); if (0.72<=t && t<=1.44) F_PROFILE(f, thread, position) = (-45.1407*(t-0.72)*(t-0.72)*(t-0.72)*(t-0.72)*(t-0.72)+ 47.2291*(t-0.72)*(t-0.72)*(t-0.72)*(t-0.72) + 11.42*(t-0.72)*(t-0.72)*(t-0.72) - 26.9213*(t-0.72)*(t-0.72) + 8.1241*(t-0.72) + 0.9117); } end_f_loop(f, thread) } Even import successfully into Fluent but it was interrupted while running. the error is: divergence detect in AMG solver:temperature how can i setup the proper parameter like time step and number of time step? Thanks advance in for any reply

You can have a try...

Run fluent --> open your case.....

Solve-->Controls--> limits--> "Temperature range"

Good luck, Braket