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Incorrect pressure results and problems with outlet BC's

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Old   December 9, 2020, 10:16
Default Incorrect pressure results and problems with outlet BC's
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Jonathan Wells
Join Date: Oct 2020
Location: Indiana
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Hello,

I'm fairly new to openfoam, and I've been trying to run a simple shear layer case using rhoPimpleFoam. I have two inlets, one high-speed and one low-speed, one outlet, and the top and bottom boundaries are freestreams with mach numbers corresponding to the adjacent inlet. I will attach a pic for clarity.

My first problem is the pressure. I tried to run an RAS to get a decent initial field prior to running LES, and the pressure is just blatantly wrong. The domain is static pressure matched, but the p field in paraFoam shows a lower pressure on the bottom (low-speed). A pic is attached of the results.

My other problem is, no matter what I do, the outlet acts as a wall. Once the flow from the inlets reaches the outlet, it doesn't move out of the domain. It just slowly builds backpressure and causes the solution to crash due to negative initial temperature. I thought this was due to making the static temperature equal everywhere in the domain (which is how I've run the simulation in both Fluent and Cobalt with no issues), but setting the outlet pressure to a value of 1 doesn't change this behavior. I will attach my pressure BC file as well.

Code:
/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2006                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       volScalarField;
    object      p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 1;

boundaryField
{
    hsinlet
    {
        type            waveTransmissive;
	value 		uniform 1e5;
	field		p;
	gamma		1.4;
	lInf		0.5;
	fieldInf	1e5;
    }

    lsinlet
    {
        type            waveTransmissive;
	value 		uniform 1e5;
	field		p;
	gamma		1.4;
	lInf		0.5;
	fieldInf	1e5;
    }

    outlet
    {
        type            fixedValue;
	value		uniform 1;
    }

    upper
    {
        type            inletOutlet;
	inletValue	uniform 1e5;

    }

    lower
    {
        type            inletOutlet;
	inletValue	uniform 1e5;
    }

    faces
    {
        type            empty;
    }
}

// ************************************************************************* //
Is there anyone who can look at this and help me out, please? I have beaten my head against a wall with this for so long that I can't see the forest for the trees so to speak. I would greatly appreciate any feedback.
Attached Images
File Type: png OFbadPressure.PNG (137.1 KB, 6 views)
File Type: jpg CompGrid.jpg (183.5 KB, 6 views)
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