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Old   July 3, 2008, 18:30
Default time-dependent_velocity
  #1
Abel
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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
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Old   July 4, 2008, 03:36
Default Re: time-dependent_velocity
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red lemon
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this is in the user guide so just copy that format.
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Old   July 4, 2008, 04:16
Default Re: time-dependent_velocity
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Abel
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Hi lemon,

Unfortunately, I have no access to user guide !

Can you please send me the corresponding format ?

Thanks.

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Old   July 4, 2008, 11:52
Default Re: time-dependent_velocity
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red lemon
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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)

}

}
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Old   July 9, 2008, 15:41
Default Re: time-dependent_velocity
  #5
abel
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Well received

thank you Lemon !

Best Regards
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