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How to update variable value every 50 iterations?

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Old   September 2, 2019, 09:55
Default How to update variable value every 50 iterations?
  #1
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Join Date: Sep 2019
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Hello Everyone,
I have been trying to write a program to compute slip velocity on a wall for a micro-nozzle, i need to update the value of relaxation every 50 iterations and have written a code for the same. But i just can't seem to get it to work.


Any help will be appreciated.


thanks in advance
(there are some redundant variables...i am still testing the code)

heres the udf :


#include "udf.h" /* must be at the beginning of every UDF */
/*#include "mem.h" /* must be at the beginning of this UDF */
//#include <math.h> /* must be at the beginning of this UDF */
/*#include "metric.h" /* must be at the beginning of this UDF */
#define k_B 1.3805e-23 /* Boltzman constant (j/K)*/
#define sigma 419e-12 /* molecular diameter*/
#define sigma_v 1 /* Tangential momentum accommodation coefficient*/
#define sigma_T 1 /*Thermal accommodation coefficient*/
#define pi 3.14159 /* pi number*/
#define sqrt_2 1.41421 /* sqrt(2) number */
//#define relax 50e-3
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f,DU,DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;
double relax = 105e-3;
double DUR, DVR;
int counter = 0;

begin_f_loop(f, t)
{
counter = counter + 1;
printf("Counter %d", counter);
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */

// Calculation of the Wall Slip Velocity
F_PROFILE(f, t, index) = relax * sin(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
if ((counter % 50) == 0)
{
relax = relax + 1e-3;
printf("The residual is : %f", counter);
}


}
end_f_loop(f, t)


}
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f, DU, DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;
double relax = 105e-3;
double DUR, DVR;
int counter = 0.0;

begin_f_loop(f, t)
{
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
/*DUR = C_U_RG(c0, t0)[1];
DVR = C_V_RG(c0, t0)[1];*/

K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */
F_PROFILE(f, t, index) = relax * cos(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
if ((counter % 50) == 0)
{
relax = relax + 1e-3;
}
counter = counter + 1;
}
end_f_loop(f, t)
}
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Old   September 3, 2019, 03:55
Default
  #2
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Alexander
Join Date: Apr 2013
Posts: 2,363
Rep Power: 35
AlexanderZ will become famous soon enoughAlexanderZ will become famous soon enough
if you are talking about timesteps (not iterations) :
Code:
#include "udf.h" /* must be at the beginning of every UDF */
/*#include "mem.h" /* must be at the beginning of this UDF */
//#include <math.h> /* must be at the beginning of this UDF */
/*#include "metric.h" /* must be at the beginning of this UDF */
#define k_B 1.3805e-23 /* Boltzman constant (j/K)*/
#define sigma 419e-12 /* molecular diameter*/
#define sigma_v 1 /* Tangential momentum accommodation coefficient*/
#define sigma_T 1 /*Thermal accommodation coefficient*/
#define pi 3.14159 /* pi number*/
#define sqrt_2 1.41421 /* sqrt(2) number */
double relax = 105e-3;
int counter = 0;
//#define relax 50e-3
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f,DU,DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;

double DUR, DVR;


begin_f_loop(f, t)
{
counter = counter + 1;
printf("Counter %d", counter);
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */

// Calculation of the Wall Slip Velocity
F_PROFILE(f, t, index) = relax * sin(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
}
end_f_loop(f, t)


}
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f, DU, DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;
double DUR, DVR;

begin_f_loop(f, t)
{
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
/*DUR = C_U_RG(c0, t0)[1];
DVR = C_V_RG(c0, t0)[1];*/

K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */
F_PROFILE(f, t, index) = relax * cos(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
}
end_f_loop(f, t)
}

DEFINE_EXECUTE_AT_END(define_relax)
{
if ((counter % 50) == 0)
{
relax = relax + 1e-3;
}
counter = counter + 1;
}
dont forget to hook DEFINE_EXECUTE_AT_END macro

best regards
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Old   September 3, 2019, 06:20
Default
  #3
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Join Date: Sep 2019
Posts: 24
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NonStopEagle is on a distinguished road
Quote:
Originally Posted by AlexanderZ View Post
if you are talking about timesteps (not iterations) :
Code:
#include "udf.h" /* must be at the beginning of every UDF */
/*#include "mem.h" /* must be at the beginning of this UDF */
//#include <math.h> /* must be at the beginning of this UDF */
/*#include "metric.h" /* must be at the beginning of this UDF */
#define k_B 1.3805e-23 /* Boltzman constant (j/K)*/
#define sigma 419e-12 /* molecular diameter*/
#define sigma_v 1 /* Tangential momentum accommodation coefficient*/
#define sigma_T 1 /*Thermal accommodation coefficient*/
#define pi 3.14159 /* pi number*/
#define sqrt_2 1.41421 /* sqrt(2) number */
double relax = 105e-3;
int counter = 0;
//#define relax 50e-3
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f,DU,DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;

double DUR, DVR;


begin_f_loop(f, t)
{
counter = counter + 1;
printf("Counter %d", counter);
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */

// Calculation of the Wall Slip Velocity
F_PROFILE(f, t, index) = relax * sin(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
}
end_f_loop(f, t)


}
DEFINE_PROFILE(wall_slip_velocity, t, index)
{
double T, P, density, MU, K, landa, a_m, du_da, dT_dx, u_f, DU, DV;
double A[ND_ND];
face_t f;
Thread* t0;
cell_t c0;
double DUR, DVR;

begin_f_loop(f, t)
{
t0 = THREAD_T0(t); /* adjacent cell thread to f */
c0 = F_C0(f, t); /* adjacent cell to f */
T = C_T(c0, t0); /* temperature of the cell */
P = C_P(c0, t0); /* peressure of the cell */
density = C_R(c0, t0); /* density of the cell*/
MU = C_MU_L(c0, t0); /* laminar viscosity of the cell */
/*DUR = C_U_RG(c0, t0)[1];
DVR = C_V_RG(c0, t0)[1];*/

K = C_K_L(c0, t0); /* thermal conductivity of the cell */
landa = (k_B * T) / (sqrt_2 * pi * sigma * sigma * P); /* mean free path line */
DU = C_DUDY(c0, t0);
DV = C_DVDY(c0, t0);
if (DU < 0)
{
DU = (-1 * DU);
}
if (DV < 0)
{
DV = (-1 * DV);
}

F_AREA(A, f, t);
a_m = NV_MAG(A); /* magnitude of the cell area vector */
du_da = NV_DOT(A, A) / a_m; /* n- component of the cell x-velocity reconstruction gradient(RG) vector */
dT_dx = 1; /* x-component of the cell temperature reconstruction gradient(RG) vector */
F_PROFILE(f, t, index) = relax * cos(22.75 * pi / 180) * (((2 - sigma_v) / sigma_v) * landa * (DU + DV) + 0.75 * (MU / (density * T)) * dT_dx);
}
end_f_loop(f, t)
}

DEFINE_EXECUTE_AT_END(define_relax)
{
if ((counter % 50) == 0)
{
relax = relax + 1e-3;
}
counter = counter + 1;
}
dont forget to hook DEFINE_EXECUTE_AT_END macro

best regards
Thanks AlexanderZ, the code works like a charm.
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