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Free surface flow in a channel: how to maintain water level |
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August 28, 2015, 02:16 |
Free surface flow in a channel: how to maintain water level
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#1 |
New Member
Meher
Join Date: Jan 2014
Posts: 13
Rep Power: 12 |
Dear all,
I am simulating free surface flow around 2D cylinder with interFoam solver using OF 2.4.0. To start with, Iaminar flow is considered. The issue is I am unable to maintain the water level in-spite of trying various boundary conditions. The rectangular domain consists of two inlets and one outlet. The bottom inlet is for water and the top inlet is for air. The top boundary is open to atmosphere. The bottom boundary condition is symmetry. I have attached the grid as well. Please look at boundary conditions and schemes and let me know where I am doing wrong. Thank you, Meher. Code:
U: boundaryField { WATERINLET { type fixedValue; value uniform (0.005 0 0); } OUTLET { type inletOutlet; inletValue uniform (0 0 0); value uniform (0 0 0); } AIRINLET { type fixedValue; value uniform (0 0 0); } BOTTOM { type symmetry; } CYLINDER { type fixedValue; value uniform (0 0 0); } ATMOSPHERE { type pressureInletOutletVelocity; value uniform (0 0 0); } frontAndBackPlanes { type empty; } } Code:
p_rgh: boundaryField { WATERINLET { type fixedFluxPressure; value uniform 0; } OUTLET { type zeroGradient; } AIRINLET { type fixedFluxPressure; value uniform 0; } BOTTOM { type symmetry; } CYLINDER { type fixedFluxPressure; value uniform 0; } ATMOSPHERE { type totalPressure; p0 uniform 0; U U; phi phi; rho rho; psi none; gamma 1; value uniform 0; } frontAndBackPlanes { type empty; } } Code:
alpha.water: boundaryField { WATERINLET { type zeroGradient; //type fixedValue; //value uniform 1; } OUTLET { type inletOutlet; inletValue uniform 0; value uniform 0; } AIRINLET { type zeroGradient; //type fixedValue; //value uniform 0; } BOTTOM { type symmetry; } CYLINDER { type zeroGradient; } ATMOSPHERE { type inletOutlet; inletValue uniform 0; value uniform 0; } frontAndBackPlanes { type empty; } } Code:
fvSchemes: ddtSchemes { default Euler; } gradSchemes { default Gauss linear; grad(U) cellLimited Gauss linear 1; } divSchemes { div(rhoPhi,U) Gauss linearUpwindV grad(U); div(phi,alpha) Gauss vanLeer; div(phirb,alpha) Gauss interfaceCompression; div((muEff*dev(T(grad(U))))) Gauss linear; } laplacianSchemes { default Gauss linear corrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; } fluxRequired { default no; p_rgh; pcorr; alpha.water; } Code:
fvSolution: solvers { "alpha.water.*" { nAlphaCorr 2; nAlphaSubCycles 1; cAlpha 1; icAlpha 0; MULESCorr yes; nLimiterIter 10; alphaApplyPrevCorr yes; solver smoothSolver; smoother symGaussSeidel; tolerance 1e-8; relTol 0; minIter 1; } pcorr { solver PCG; preconditioner DIC; tolerance 1e-10; relTol 0; } p_rgh { solver PCG; preconditioner DIC; tolerance 1e-07; relTol 0.05; } p_rghFinal { solver PCG; preconditioner DIC; tolerance 1e-07; relTol 0; } "(U|k|epsilon)" { solver PBiCG; preconditioner DILU; tolerance 1e-06; relTol 0; } "(U|k|epsilon)Final" { solver PBiCG; preconditioner DILU; tolerance 1e-08; relTol 0; } } PIMPLE { momentumPredictor no; nCorrectors 2; nNonOrthogonalCorrectors 0; nAlphaCorr 1; nAlphaSubCycles 3; cAlpha 1; pRefCell 0; pRefValue 0; } relaxationFactors { fields { } equations { ".*" 1; } } |
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September 2, 2015, 21:43 |
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#2 |
Senior Member
Matthew Denno
Join Date: Feb 2010
Posts: 138
Rep Power: 16 |
Meher,
Unfortunately, I don't have a great solution to this problem. It is something that I have struggled with. I have a few suggestions that might work though. 1) you could try setting the initial internal velocity field to match the inlet velocity with setFields. 2) you could try to set the outlet velocity boundary the same as the inlet (only negative). Hope these work for you. |
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September 3, 2015, 01:43 |
Re: Re: Help regardfng free surface flow in a channel using interfoam
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#3 |
New Member
Meher
Join Date: Jan 2014
Posts: 13
Rep Power: 12 |
Dear Matthew,
Thank you for your reply. I have already tried these options you suggested. All these changes are only delaying the inevitable (water level decreasing) but not completely overcoming it. At times, the water level may start decreasing at 15.0 s., at times at 50 s. But it is bound to happen. Anyhow, I will attempt your suggestions again and let you know if I notice any substantial change. Currently, I am trying to refine the mesh and see how it goes. Meher. |
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March 24, 2017, 17:42 |
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#4 |
Member
Bashar
Join Date: Jul 2015
Posts: 74
Rep Power: 11 |
Hi,
I am simulating close problem to yours. I also have unstable free surface when simulating flow past plate . I tried different combinations of BC with no luck. Do you manage to solve the free surface issue. |
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March 25, 2017, 07:35 |
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#5 |
New Member
Meher
Join Date: Jan 2014
Posts: 13
Rep Power: 12 |
Bashar,
I did solve my issue. Can you please share your case setup so that I can have a look at it? Meher. |
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March 25, 2017, 20:12 |
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#6 | |
Member
Bashar
Join Date: Jul 2015
Posts: 74
Rep Power: 11 |
Quote:
Thank you Meher, In the link below you will find a full description for my case with a history of what I have done until this moment. Many thanks for your input. Bashar Wrong BC for VOF simulation using interFoam for flow past plate with k-omega-sst |
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Tags |
channel flow, free surface flow, interfoam, of2.4.0, water level decreasing |
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