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Old   March 27, 2017, 06:58
Default UDF velocity inlet sinusoidal profile
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Douaa Al-Assaad
Join Date: Feb 2017
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I am assigning to a certain inlet that i have a sinusoidal profile for velocity and everything was working fine,
however i wanted to add a random perturbation to my sine function in the udf to obtain a sinuosoid with some noise.
When i modified my code, fluent did not feel this perturbation much and the profile was still sinusoidal with no noise.

I am attaching my code below:

#include "udf.h"
#include <cstdlib>
#include <ctime>
#include <cmath>
#define w 2.1
#define T 3
#define m 1

DEFINE_PROFILE(inlet_velocity, thread, index)
real time = RP_Get_Real("flow-time");
face_t f;
real func;

srand((unsigned int)time(NULL));
double Rnd;
Rnd= rand()%10001/10000.00;
v1 = 2.815+(0.775*sin(2*3.1416*0.5*time));
v2 = 2.765+(0.775*sin(2*3.1416*0.5*time));
noise =(v1-v2)*Rnd;

//face_t f;
//real func;
//real time = RP_Get_Real("flow-time");

if (time<1)
func = 0;
func= ((v1+v2)/2)+ pow(-1.0,(floor)(10*Rnd))*noise;

begin_f_loop(f, thread) // loop over all faces in the thread passed in the DEFINE_PROFILE macro argument
F_PROFILE(f, thread, index) = func;
end_f_loop(f, thread)

Does anyone have an idea on why it wouldn't take the function that I gave it?

Thank you
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