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Tad February 15, 2005 09:45

mass residual
 
I am using CFX 4.4, to simulate incompressible flow using the default descretisation schemes. After the simulation is finished, I break the dump file using matlab and get information of UVELOCITY,VVELOCITY WVELOCITY, DENSITY mass residual and area of the six faces of each control volume. However when I calculate the mass balance by multiplying each component of the velocity with the perpendicular area, the residual is always by far greater than the one extracted from the dump file. The situation is getting worse when the control volume lies on the boundary. I made the velocities calculation at cell faces from cell centre values using weighted linear interpolation scheme based on relative distance in physical phases as described on the manual. May I request you to help me with this matter? Secondly, Is there some special treatment of the dummy cells at the walls, inlet and outlet?

Thank you in advance for your cooperation

Tad


Jeff February 17, 2005 00:30

Re: mass residual
 
There's an array called CONV which stores the mass fluxes at all of the faces. Using these values at each cell face times the face areas should give you the proper mass balance on the cell.

Jeff

Tad February 17, 2005 10:52

Re: mass residual
 
Thanks Jeff


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