# Coefficients in Simple algorithm with staggered mesh.

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 January 22, 2015, 02:35 Coefficients in Simple algorithm with staggered mesh. #1 New Member   Felipe Muñoz Flores Join Date: Jan 2015 Posts: 4 Rep Power: 8 I am programming SIMPLE algorithm with a staggered mesh in 2D. According to the Patankar's Book, first I have to solve the momentum equations for u* and v* for a given pressure fiel p* (eq 6.8 and 6.9, page 122), but i dont know where the neighbor coefficients a_n en y direction are placed for u momentum eq. and coefficients in x direction for v momentum eq. These coefficients depends of the diffusion and mass flux terms which falls in the middle of control volume where I don't have grid points. I hope you understand me, thank you very much.

January 22, 2015, 09:17
#2
Senior Member

p ding
Join Date: Mar 2009
Posts: 380
Rep Power: 14
Quote:
 Originally Posted by pipenx I am programming SIMPLE algorithm with a staggered mesh in 2D. According to the Patankar's Book, first I have to solve the momentum equations for u* and v* for a given pressure fiel p* (eq 6.8 and 6.9, page 122), but i dont know where the neighbor coefficients a_n en y direction are placed for u momentum eq. and coefficients in x direction for v momentum eq. These coefficients depends of the diffusion and mass flux terms which falls in the middle of control volume where I don't have grid points. I hope you understand me, thank you very much.
Dear friends:
any coefficient on the interface is interpolated from its neighbor nodes.
you may have a look at the patankar's book, about the "harmonic interpolation" of the diffusion coefficients.

 January 22, 2015, 13:29 #3 New Member   Felipe Muñoz Flores Join Date: Jan 2015 Posts: 4 Rep Power: 8 Thanks, effectively I am calculating the coefficients by harmonic interpolation. For the momentum eq. for u i don't have any problem for eE and eW coefficients because these are located in E and P nodos of the non staggered grid but for the case eN and eS I don't understand where i have to calculated de coefficients. I appreciate your help.

January 22, 2015, 19:16
#4
Senior Member

p ding
Join Date: Mar 2009
Posts: 380
Rep Power: 14
Quote:
 Originally Posted by pipenx Thanks, effectively I am calculating the coefficients by harmonic interpolation. For the momentum eq. for u i don't have any problem for eE and eW coefficients because these are located in E and P nodos of the non staggered grid but for the case eN and eS I don't understand where i have to calculated de coefficients. I appreciate your help.
hope this helpy you.
use the concept of the "parallel heat transfer resistance theory "and "serial heat transfer resistance theroy"
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 Tags momentum coeficient, momentum equation, simple algorithm