Help with switching solver cases

lth · March 6, 2009, 15:42

I am new to OpenFOAM and struggling to learn the structure(path) of how a solver works with dictionary files. The tutorial does not seem to show steps too much on such a procedure when changing solvers.

For a quick example, I run the cavity flow tutorial with icoFoam. Then change application to nonNewtonianIcoFoam in systems/controlDict, and copy nonNewtonianIcoFoam/offsetCylinder/constants/transportProperties. When I call nonNewtonian solver with this case, the soln diverges and i am not familiar enough to debug.

Thanks for any insight. LTH

marico · March 9, 2009, 02:41

Hi,

try also to copy the fvSchemes file, which describes how the equations are treated. Probably there is a difference between newton and non-newton fluids. More fundamental description about this is in the users guide!

Best Regards
Marco

lth · March 9, 2009, 11:26

Marco,

Thank you, it's running now. The Courant number was blowing up so I lowered the delta_T to 0.00005 before it would converge. Not sure why it needed to go so low but assume the cavity mesh needs refinement near the edges for the nonNewtonian case.

Lori Holmes

March 6, 2009, 15:42	I am new to OpenFOAM and strug	#1
lth Member lth Join Date: Mar 2009 Location: Madison, WI, USA Posts: 37 Blog Entries: 45 Rep Power: 17	I am new to OpenFOAM and struggling to learn the structure(path) of how a solver works with dictionary files. The tutorial does not seem to show steps too much on such a procedure when changing solvers. For a quick example, I run the cavity flow tutorial with icoFoam. Then change application to nonNewtonianIcoFoam in systems/controlDict, and copy nonNewtonianIcoFoam/offsetCylinder/constants/transportProperties. When I call nonNewtonian solver with this case, the soln diverges and i am not familiar enough to debug. Thanks for any insight. LTH

March 9, 2009, 02:41	Hi, try also to copy the fv	#2
marico Member Marco Müller Join Date: Mar 2009 Location: Germany Posts: 94 Rep Power: 17	Hi, try also to copy the fvSchemes file, which describes how the equations are treated. Probably there is a difference between newton and non-newton fluids. More fundamental description about this is in the users guide! Best Regards Marco

March 9, 2009, 11:26	Marco, Thank you, it's run	#3
lth Member lth Join Date: Mar 2009 Location: Madison, WI, USA Posts: 37 Blog Entries: 45 Rep Power: 17	Marco, Thank you, it's running now. The Courant number was blowing up so I lowered the delta_T to 0.00005 before it would converge. Not sure why it needed to go so low but assume the cavity mesh needs refinement near the edges for the nonNewtonian case. Lori Holmes

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