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Release injection each time step in Fluent 14

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Old   October 31, 2012, 03:35
Default Release injection each time step in Fluent 14
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JenFeg
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Hello,
I'm solving unsteady flow with steady DPM particles. So, I'd like to set up injection to be released only once in each time-step (probably at beggining of time-step).

I could not find this settings, can give a hint ?
Thank you.
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Old   November 1, 2012, 11:29
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Pedram Mojtabavi
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You need to setup a boundary with pulsed on/off type injection?
You can write an UDF to define these type of boundary by using a step function.
You can use a simple SIN or COS to define that, for exmaple:
F(x) = |sin(pi*t/2)|;
The function produces 0 ,1 periodically with the progression of time =1,2,3,...
I have a code here specifically for on/off injection you can use:

************************************************** ******
#include "udf.h"
DEFINE_PROFILE(injection_pulsed_flux, thread, position)
{
face_t f;
real t = CURRENT_TIME;
int n;
real pi;
n = 1000000.*t/1.7;
pi = 1.570796;
begin_f_loop(f, thread)
{
F_PROFILE(f, thread, position) = 100.*fabs(sin(pi*n));
}
end_f_loop(f, thread)
}
************************************************** ****
You need to replace you own 1/(delta t) where I have underlined (mine was 1e-6). The F profile will generate a specific number and zero. The "100" could be replaced by your own case's value.

Hope it could help,
Best regards.
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Old   February 13, 2013, 00:47
Default Dpm model
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santhosh
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Hai sir/Madam

I am using fluent software for my dpm injections ina GDI engines.Using pressure swirl atomizer i got injectios in the form of V shape instaed of a circular shape in 3d model.Please tell me which parameter does it depend on it. and how to modify.

Thank u

Santhosh Kumar K
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