# Lattice Boltzmann method_Thermal Poiseuille flow

 Register Blogs Members List Search Today's Posts Mark Forums Read

 September 9, 2017, 13:43 Lattice Boltzmann method_Thermal Poiseuille flow #1 Member   shikha Join Date: Aug 2013 Posts: 40 Rep Power: 11 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

 September 9, 2017, 13:47 #2 Member   shikha Join Date: Aug 2013 Posts: 40 Rep Power: 11 I am not getting the results

September 9, 2017, 18:39
#3
Senior Member

Lane Carasik
Join Date: Aug 2014
Posts: 692
Rep Power: 13
Quote:
 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.

 September 10, 2017, 06:24 #4 Member   shikha Join Date: Aug 2013 Posts: 40 Rep Power: 11 I am not getting the result: The temperature profile is not correct

September 10, 2017, 23:02
#5
Senior Member

Lane Carasik
Join Date: Aug 2014
Posts: 692
Rep Power: 13
Quote:
 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.