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Lattice Boltzmann method_Thermal Poiseuille flow

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Old   September 9, 2017, 14:43
Default Lattice Boltzmann method_Thermal Poiseuille flow
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shikha
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Hello Friends,

I am working on a Thermal Poiseuille flow problem using lattice Boltzmann method. The problem statement is the top and bottom boundaries are assigned with hot temperature and left and right open boundaries are set with zero (non-dimensional) BC.
Here is a sample code:
for(i=0;i<=nx;i++)
{
g[i][ny][4]=(t_t*(w_f[4]+w_f[2]))-g[i][ny][2]; //Dirichlet boundary condition
g[i][ny][7]=(t_t*(w_f[5]+w_f[7]))-g[i][ny][5];
g[i][ny][8]=(t_t*(w_f[8]+w_f[6]))-g[i][ny][6];

g[i][0][2]=(t_b*(w_f[4]+w_f[2]))-g[i][0][4];
g[i][0][5]=(t_b*(w_f[5]+w_f[7]))-g[i][0][7];
g[i][0][6]=(t_b*(w_f[6]+w_f[8]))-g[i][0][8];
}

/*---------------------left and right boundary condition----------------*/

for(j=0;j<=ny;j++)
{
g[0][j][1]=-g[0][j][3];
g[0][j][5]=-g[0][j][7];
g[0][j][8]=-g[0][j][6];

g[nx][j][3]=2*g[nx-1][j][3]-g[nx-2][j][3];
g[nx][j][6]=2*g[nx-1][j][3]-g[nx-2][j][7];
g[nx][j][7]=2*g[nx-1][j][3]-g[nx-2][j][6];

However, I am getting the correct result and unable to understand where I am going wrong. Please if anyone can enlighten me. Thanks in advance.

Shikha
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Old   September 9, 2017, 14:47
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I am not getting the results
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Old   September 9, 2017, 19:39
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Lane Carasik
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Quote:
Originally Posted by SHIKHA BHUYAN View Post
Hello Friends,

I am working on a Thermal Poiseuille flow problem using lattice Boltzmann method. The problem statement is the top and bottom boundaries are assigned with hot temperature and left and right open boundaries are set with zero (non-dimensional) BC.
Here is a sample code:
for(i=0;i<=nx;i++)
{
g[i][ny][4]=(t_t*(w_f[4]+w_f[2]))-g[i][ny][2]; //Dirichlet boundary condition
g[i][ny][7]=(t_t*(w_f[5]+w_f[7]))-g[i][ny][5];
g[i][ny][8]=(t_t*(w_f[8]+w_f[6]))-g[i][ny][6];

g[i][0][2]=(t_b*(w_f[4]+w_f[2]))-g[i][0][4];
g[i][0][5]=(t_b*(w_f[5]+w_f[7]))-g[i][0][7];
g[i][0][6]=(t_b*(w_f[6]+w_f[8]))-g[i][0][8];
}

/*---------------------left and right boundary condition----------------*/

for(j=0;j<=ny;j++)
{
g[0][j][1]=-g[0][j][3];
g[0][j][5]=-g[0][j][7];
g[0][j][8]=-g[0][j][6];

g[nx][j][3]=2*g[nx-1][j][3]-g[nx-2][j][3];
g[nx][j][6]=2*g[nx-1][j][3]-g[nx-2][j][7];
g[nx][j][7]=2*g[nx-1][j][3]-g[nx-2][j][6];

However, I am getting the correct result and unable to understand where I am going wrong. Please if anyone can enlighten me. Thanks in advance.

Shikha
What exactly is your issue? You said you are getting the correct result.
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Old   September 10, 2017, 07:24
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shikha
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I am not getting the result:

The temperature profile is not correct
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Old   September 11, 2017, 00:02
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Quote:
Originally Posted by SHIKHA BHUYAN View Post
I am not getting the result:

The temperature profile is not correct
How is it not correct? You're not providing enough detail.
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