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-   -   Coefficients in Simple algorithm with staggered mesh. (https://www.cfd-online.com/Forums/main/147465-coefficients-simple-algorithm-staggered-mesh.html)

pipenx January 22, 2015 02:35

Coefficients in Simple algorithm with staggered mesh.
 
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.

ztdep January 22, 2015 09:17

Quote:

Originally Posted by pipenx (Post 528536)
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.

pipenx January 22, 2015 13:29

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.
http://thumbs.subefotos.com/4124e187...933985a90o.jpg

ztdep January 22, 2015 19:16

2 Attachment(s)
Quote:

Originally Posted by pipenx (Post 528662)
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.
http://thumbs.subefotos.com/4124e187...933985a90o.jpg

hope this helpy you.
use the concept of the "parallel heat transfer resistance theory "and "serial heat transfer resistance theroy"


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