inlet and outlet BCs for airfoil simulation

michel1988 · July 9, 2013, 06:09

Hello,
I want to do a simulation of airfoil. At inlet, the velocity is fixed and there is no restriction on the pressure (which means the pressure is calculated). At outlet, the pressure is fixed and there is no restriction on the velocity. In OpenFOAM, we must define boundry conditions for each physical quantity at each boundry. My question is : what boundry conditions should be given to pressure at inlet and to velocity at outlet? It is the first time for me to do such a simulation and I am also not familiar with BCs in OpenFOAM. Thanks for your help!

achyutan · July 9, 2013, 08:35

Hi,

'zeroGradient' b.c is best suited,among the compiled library of openfoam, for ur case. it takes value of next interior cell (which is calculated based on ur system of eqns).

if you are not satisfied with that, you can create your own new b.c and compile it and link its executable from controlDict.

achyutan

Artur · July 9, 2013, 12:12

I tend to use zeroGradient as well, sometimes I go for inletOutlet or outletInlet. For the pressure you may also consider fixedValue uniform 0 at the outlet if your domain is long enough.

July 9, 2013, 06:09	inlet and outlet BCs for airfoil simulation	#1
michel1988 New Member LI Bo Join Date: Apr 2013 Posts: 13 Rep Power: 13	Hello, I want to do a simulation of airfoil. At inlet, the velocity is fixed and there is no restriction on the pressure (which means the pressure is calculated). At outlet, the pressure is fixed and there is no restriction on the velocity. In OpenFOAM, we must define boundry conditions for each physical quantity at each boundry. My question is : what boundry conditions should be given to pressure at inlet and to velocity at outlet? It is the first time for me to do such a simulation and I am also not familiar with BCs in OpenFOAM. Thanks for your help!

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July 9, 2013, 08:35		#2
achyutan Member Join Date: Sep 2012 Posts: 60 Rep Power: 14	Hi, 'zeroGradient' b.c is best suited,among the compiled library of openfoam, for ur case. it takes value of next interior cell (which is calculated based on ur system of eqns). if you are not satisfied with that, you can create your own new b.c and compile it and link its executable from controlDict. achyutan

July 9, 2013, 12:12		#3
Artur Senior Member Artur Join Date: May 2013 Location: Southampton, UK Posts: 372 Rep Power: 20	I tend to use zeroGradient as well, sometimes I go for inletOutlet or outletInlet. For the pressure you may also consider fixedValue uniform 0 at the outlet if your domain is long enough.