time-dependent_velocity

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 July 3, 2008, 18:30 time-dependent_velocity #1 Abel Guest   Posts: n/a Hi, I have a time dependent inlet velocity : Ux = 100*time, if time < = 4 Ux = 400, otherwise Please, How to write the correspondant UDF in C language ? Thanks

 July 4, 2008, 03:36 Re: time-dependent_velocity #2 red lemon Guest   Posts: n/a this is in the user guide so just copy that format.

 July 4, 2008, 04:16 Re: time-dependent_velocity #3 Abel Guest   Posts: n/a Hi lemon, Unfortunately, I have no access to user guide ! Can you please send me the corresponding format ? Thanks.

 July 4, 2008, 11:52 Re: time-dependent_velocity #4 red lemon Guest   Posts: n/a heres a udf for mass as a function of time so you should be able to mod for velocity then hook into the bc panel: /* UDF for setting target mass flow rate in pressure-outlet */ /* at t<0.2 sec the target mass flow rate set to 1.00 kg/s */ /* when t>0.2 sec the target mass flow rate will change to 1.35 kg/s */ #include "udf.h" DEFINE_PROFILE(tm_pout2, t, nv) { face_t f ; real flow_time = RP_Get_Real("flow-time"); if (flow_time < 0.2 ) { printf("Time = %f sec. \n",flow_time); printf("Targeted mass-flow rate set at 1.0 kg/s \n"); begin_f_loop(f,t) { F_PROFILE(f,t,nv) = 1.0 ; } end_f_loop(f,t) } else { printf("Time = %f sec. \n",flow_time); printf("Targeted mass-flow rate set at 1.35 kg/s \n") ; begin_f_loop(f,t) { F_PROFILE(f,t,nv) = 1.35 ; } end_f_loop(f,t) } }

 July 9, 2008, 15:41 Re: time-dependent_velocity #5 abel Guest   Posts: n/a Well received thank you Lemon ! Best Regards

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