[SHIKHA BHUYAN]

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

[SHIKHA BHUYAN]

I am not getting the results

[lcarasik]

Originally Posted by SHIKHA BHUYAN

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.

[SHIKHA BHUYAN]

I am not getting the result:

The temperature profile is not correct

[lcarasik]

Originally Posted by SHIKHA BHUYAN

I am not getting the result:

The temperature profile is not correct

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