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-   -   Momentum Interpolation on Collocated grids (http://www.cfd-online.com/Forums/main/11561-momentum-interpolation-collocated-grids.html)

 Naresh June 1, 2006 17:30

Momentum Interpolation on Collocated grids

Hello

I have constructed a code that solves flow problems on collocated grids with momentum interpolation scheme for the face velocities. The code is working fine. However, at very low grid sizes, the solution is not there and I believe that the extra terms (added dissipation terms) in the momentuminterpolation is affecting the velocity profile. However, pressure checkerboarding is eliminated.

In addition, the scheme seems to be working for larger grids. Any suggestions????

 George June 1, 2006 19:58

Re: Momentum Interpolation on Collocated grids

Hi, when you say that the solution is not there, what do you mean exactly? And how low grid size have you tried?

 Naresh June 1, 2006 20:55

Re: Momentum Interpolation on Collocated grids

Hi there

What i try to mean is the establishment of fully developed flow near the exit.Beacuse, i impose fully developed flow for u and v velocities at the exit. I see this trend until grid sizes of 9 by 9- cartesian grid volumes.

My intuitive understanding of this situation is that the added dissipation terms have an adverse effect- but i'm not sure!

 jyothishkumar November 17, 2009 09:30

colocated grid solver

Hi Naresh,

I have written a code using simple algorithm for incompressible flow using staggered grid. Now i am trying to write the same on the colocated grid. I have done as follows. Please check whether they are right.

steps

(i). solving for up and vp without pressure term from general discretized momentum equation

(ii) Using the rho and chi's interpolation i am finding the face velocities

For eg. (u velocity at the east face of point p)
Ue = 0.5*(UP+UE) + (delv/4*ap*delx)*(PEE-3PE+3PP-PW)

(iii). Substituting the value of Ue, Uw, Un and Us in the pressure correction equation.

(iv) correcting the pressure and velocities

Whether the above steps are right ? or do i need any change in that ?

thanks

jyo

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