CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   CD-adapco (http://www.cfd-online.com/Forums/cd-adapco/)
-   -   mrf (http://www.cfd-online.com/Forums/cd-adapco/52838-mrf.html)

Lorenzo Arcangeli March 1, 2002 08:24

mrf
 
When using mrf explicit, which values I must assign to coupled boundary inlet-pressure at the interface to obtain a correct solution ?

Lorenzo Arcangeli

ccy March 2, 2002 12:41

Re: mrf
 
you can use boundary couple command. The default tolerence should work well.

LORENZO ARCANGELI March 3, 2002 06:56

Re: mrf
 
I used region couple command, but I don't know which values to assign to coupled boundaries. I tried to assign 0 to both inlet and pressure, but it seems not to be mass flux between the static and rotating region,and the pressure field is not continuos.

Thank you for helping me,

Lorenzo

john March 4, 2002 06:04

Re: mrf
 
You have to assign some reasonable values to start the flow. For example, you have boundaries like this:

=>INLET ||Coupled => PRESSURE

pressure | Inlet

At coupled inlet, you can assign a velocity which will have same mass flow rate at INLET. And the coupled pressure, the pressure must be higher than outlet PRESSURE.

The values does not need to be exact since these will be updated as part of the solution, but must be "reasonable" for flow to start.

I hope it helps.

LORENZO March 7, 2002 06:37

Re: mrf
 
Thank you for your answer,but I have a doubt,I can fix the same mass flux at the coupled inlet only if I do an uncompressible run, because I know density....and if the calculation is compressible?

Thank you,

Lorenzo

john March 8, 2002 14:58

Re: mrf
 
It really does not matter: you are only giving approximate boundary conditions to start the flow: the real boundary condition will be obtained as part of the solution.


All times are GMT -4. The time now is 04:03.