Apply wallfunction in LES

fs82 · April 14, 2010, 04:37

Hello Guys,

I want to apply a wall function to a wall in my LES simulation. After consulting the User Guide the boundaryField part of my 0/nuSgs file looks like this:

boundaryField
{
top
{
type zeroGradient;
}
bottom
{
type nuSgsWallFunction;
value uniform 1;
}
p1
{
type cyclic;
}
p2
{
type cyclic;
}
}

Testing this with pisoFoam and oneEqEddy SGS Model the solver runs. If I now change the nuSgsWallFunction to e.g. "bla" nothing happens, the solver is still running without any problems. Furthermore if I apply my own wallFunction (change nuSgsWallFunction to moninObukhovWallFunction) where I added: Info << "Wall function is working " << endl; to the evaluate subroutine the solver still runs without any problems but I do not see the Info text on my screen which leads my to the assumption my wallFunction is not used. Have I forgot something to enable? Or is there a bug?

kind regards,
Fabian

fs82 · April 14, 2010, 08:06

Allright I dont know why, but after hours of trying it works now ...

panda60 · April 16, 2010, 04:03

I also have met the same problem. So I don't know if the solver is using the wallFunction or not.

fs82 · April 16, 2010, 07:14

I tested this a little bit and this is not only a problem for wall functions. OpenFoam don't check if the type of boundary condition is valid. Even if you misspelled the type but you have set a value OpenFoam assumes a fixedValue type BC as default and do not inform you about your mistake. This is not a bug, but it would be good to give a hint to the user if using default.

April 14, 2010, 04:37	Apply wallfunction in LES	#1
fs82 Senior Member Dr. Fabian Schlegel Join Date: Apr 2009 Location: Dresden, Germany Posts: 222 Rep Power: 17	Hello Guys, I want to apply a wall function to a wall in my LES simulation. After consulting the User Guide the boundaryField part of my 0/nuSgs file looks like this: boundaryField { top { type zeroGradient; } bottom { type nuSgsWallFunction; value uniform 1; } p1 { type cyclic; } p2 { type cyclic; } } Testing this with pisoFoam and oneEqEddy SGS Model the solver runs. If I now change the nuSgsWallFunction to e.g. "bla" nothing happens, the solver is still running without any problems. Furthermore if I apply my own wallFunction (change nuSgsWallFunction to moninObukhovWallFunction) where I added: Info << "Wall function is working " << endl; to the evaluate subroutine the solver still runs without any problems but I do not see the Info text on my screen which leads my to the assumption my wallFunction is not used. Have I forgot something to enable? Or is there a bug? kind regards, Fabian

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April 14, 2010, 08:06		#2
fs82 Senior Member Dr. Fabian Schlegel Join Date: Apr 2009 Location: Dresden, Germany Posts: 222 Rep Power: 17	Allright I dont know why, but after hours of trying it works now ...

April 16, 2010, 04:03		#3
panda60 Senior Member Jiang Join Date: Oct 2009 Location: Japan Posts: 186 Rep Power: 16	I also have met the same problem. So I don't know if the solver is using the wallFunction or not.

April 16, 2010, 07:14		#4
fs82 Senior Member Dr. Fabian Schlegel Join Date: Apr 2009 Location: Dresden, Germany Posts: 222 Rep Power: 17	I tested this a little bit and this is not only a problem for wall functions. OpenFoam don't check if the type of boundary condition is valid. Even if you misspelled the type but you have set a value OpenFoam assumes a fixedValue type BC as default and do not inform you about your mistake. This is not a bug, but it would be good to give a hint to the user if using default.