Learning Forum

[Paul Richter]

Hello,

i am doing a transient simulation with a DPM Injection.

I want the injection not to be constant but to be a function of the simulation time (for example t^2).

I think that the only way to implement that is with a UDF, i came up with this Code, but it is not working at all:

#include "udf.h"

DEFINE_DPM_SOURCE(dpm_mass_flow, c, t, initialize, p)
{
    real time = CURRENT_TIME;
    real mass_flow_rate;

    mass_flow_rate = time * time;

    return mass_flow_rate;
}

My questions are:

1) Is there an easier way to achieve a total flow rate of t^2

2) If not do you know a better option for a UDF Code?

Thanks in advance

[Rob]

Have a look at DEFINE_DPM_INJECTION_INIT   

[Paul Richter]

Dear Rob,

first of all thanks for your reply!

Yes i came up with this too, i made the Code:

#include "udf.h"

DEFINE_DPM_INJECTION_INIT(init,I)
{
    Particle *p;
    real time = CURRENT_TIME;
    real P_FLOW_RATE;
   
    // Einstellung der Partikelmasse
    P_FLOW_RATE(p) = time * time;
}

But i get the Error "P_FLOW_RATE: no function prototype"

[Rob]

Which manual are you reading? 

[Paul Richter]

 

ANSYS FLUENT 12.0 UDF - edit Rob to comply with copyright

 

 

[Rob]

That'll explain it. Use the documentation that comes with the software (click on Help). You're using the old form of the macro.