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-   -   Incompressible axisymmetric sudden expansion (https://www.cfd-online.com/Forums/openfoam-solving/58796-incompressible-axisymmetric-sudden-expansion.html)

samarth June 17, 2008 17:00

Hi I have been running a si
 
Hi

I have been running a simulation for an axisymmetric device with a sudden expansion. The working material is Nitrogen. I have run the simulation using fluent and openfoam. The results that I got from fluent are closer to experimental results that I got from a paper. The boundary conditions that I used in fluent are :
1)entrance : Constant inlet velocity of 1 m/s.
2)Wall: Adiabatic no slip
3)Exit: Constant pressure 1 atm (zero gauge)

I am getting a difference in the solutions that I get from both softwares. The solutions are qualitatively similar. The difference lies in the reattachment lengths. Fluent gives me a reattachment length that is closer to the one mentioned in the paper. Am I making a mistake in the boundary conditions in openfoam.

The bc's in openFOAM are as follows

boundaryField
{
velocity-inlet-6
{
type fixedValue;
value uniform (1 0 0);
}

pressure-outlet-5
{
type zeroGradient;
}

wall-4
{
type fixedValue;
value uniform (0 0 0);
}
}

Thanks in advance for any help


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