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October 18, 2011, 20:06 |
How should I set these boundary conditions?
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#1 |
New Member
S Park
Join Date: Oct 2011
Posts: 2
Rep Power: 0 |
Hi, I am trying to set up a very simple problem with
three inlets coming from left and one outlet going out (to right). I want the inlets to have certain pressure values & speed. For simplicity, I ran it with potentialFoam solver. However, after running the code, it seems like the flow is not going through the outlet; instead, it seems like the flow is flowing from motive inlet and exiting to suction inlets. Can someone help me how should I fix these boundary conditions? Thank you in advance! (suctiontop & suctionbottom & motive are inlets.) For U: FoamFile { version 2.0; format ascii; class volVectorField; location "0"; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { down { type symmetryPlane; } outlet { type zeroGradient; } top { type symmetryPlane; } motive { type fixedValue; value uniform (0 0 0); } suctiontop { type fixedValue; value uniform (0 0 0); } suctionbottom { type fixedValue; value uniform (0 0 0); } defaultFaces { type empty; } } // ************************************************** *********************** // For P: FoamFile { version 2.0; format ascii; class volScalarField; object p; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 2 -2 0 0 0 0]; internalField uniform 0; boundaryField { down { type symmetryPlane; } top { type symmetryPlane; // zeroGradient; //symmetryPlane; } motive { type fixedValue ; value uniform 5; } suctionbottom { type fixedValue ; value uniform 1; } suctiontop { type fixedValue ; //zeroGradient; value uniform 1; } outlet { type zeroGradient } defaultFaces { type empty; } } |
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October 19, 2011, 02:56 |
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#2 |
Senior Member
Steven van Haren
Join Date: Aug 2010
Location: The Netherlands
Posts: 149
Rep Power: 15 |
Why do you want to have inlets with a fixed pressure? I assume u solve for incompressible flow.
To me it is not strange that the fluid is moving from the high pressure inlet to the low pressure inlets. I think the standard combination is fixedValue U/zeroGradient p for inlets and zeroGradient U/fixedValue p for outlets. |
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October 19, 2011, 05:13 |
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#3 |
Senior Member
Roman Thiele
Join Date: Aug 2009
Location: Eindhoven, NL
Posts: 374
Rep Power: 20 |
if you want pressure driven flows you should take a look at the appropriate boundary conditions,
pressureInletOutletVelocity pressureInletUniformVelocity and some of the others that have to do with pressure velocities, those will set your velocity due to a set pressure. you can find the different boundary conditions under /opt/openfoam201/src/finiteVolume/fields/fvPatchFields/derived
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~roman |
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