OpenFOAM-dev / data /src /finiteVolume /fields /fvPatchFields /derived /plenumPressure /plenumPressureFvPatchScalarField.H
| /*---------------------------------------------------------------------------*\ | |
| ========= | | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | |
| \\ / O peration | Website: https://openfoam.org | |
| \\ / A nd | Copyright (C) 2016-2026 OpenFOAM Foundation | |
| \\/ M anipulation | | |
| ------------------------------------------------------------------------------- | |
| License | |
| This file is part of OpenFOAM. | |
| OpenFOAM is free software: you can redistribute it and/or modify it | |
| under the terms of the GNU General Public License as published by | |
| the Free Software Foundation, either version 3 of the License, or | |
| (at your option) any later version. | |
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| for more details. | |
| You should have received a copy of the GNU General Public License | |
| along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>. | |
| Class | |
| Foam::plenumPressureFvPatchScalarField | |
| Description | |
| This boundary condition provides a plenum pressure inlet condition. This | |
| condition creates a zero-dimensional model of an enclosed volume of gas | |
| upstream of the inlet. The pressure that the boundary condition exerts on | |
| the inlet boundary is dependent on the thermodynamic state of the upstream | |
| volume. The upstream plenum density and temperature are time-stepped along | |
| with the rest of the simulation, and momentum is neglected. The plenum is | |
| supplied with a user specified mass flow and temperature. | |
| The result is a boundary condition which blends between a pressure inlet | |
| condition condition and a fixed mass flow. The smaller the plenum | |
| volume, the quicker the pressure responds to a deviation from the supply | |
| mass flow, and the closer the model approximates a fixed mass flow. As | |
| the plenum size increases, the model becomes more similar to a specified | |
| pressure. | |
| The expansion from the plenum to the inlet boundary is controlled by an | |
| area ratio and a discharge coefficient. The area ratio can be used to | |
| represent further acceleration between a sub-grid blockage such as fins. | |
| The discharge coefficient represents a fractional deviation from an | |
| ideal expansion process. | |
| This condition is useful for simulating unsteady internal flow problems | |
| for which both a mass flow boundary is unrealistic, and a pressure | |
| boundary is susceptible to flow reversal. It was developed for use in | |
| simulating confined combustion. | |
| Reference: | |
| \verbatim | |
| Bainbridge, W. (2013). | |
| The Numerical Simulation of Oscillations in Gas Turbine Combustion | |
| Chambers, | |
| PhD Thesis, | |
| Chapter 4, Section 4.3.1.2, 77-80. | |
| \endverbatim | |
| Usage | |
| \table | |
| Property | Description | Required | Default value | |
| gamma | ratio of specific heats | yes | none | |
| R | specific gas constant | yes | none | |
| supplyMassFlowRate | flow rate into the plenum | yes | none | |
| supplyTotalTemperature | temperature into the plenum | yes | none | |
| plenumVolume | plenum volume | yes | none | |
| plenumDensity | plenum density | yes | none | |
| plenumTemperature | plenum temperature | yes | none | |
| U | velocity field name | no | U | |
| phi | flux field name | no | phi | |
| rho | inlet density | no | none | |
| inletAreaRatio | inlet open fraction | yes | none | |
| inletDischargeCoefficient | inlet loss coefficient | yes | none | |
| timeScale | relaxation time scale | yes | none | |
| \endtable | |
| Example of the boundary condition specification: | |
| \verbatim | |
| <patchName> | |
| { | |
| type plenumPressure; | |
| gamma 1.4; | |
| R 287.04; | |
| supplyMassFlowRate 0.0001; | |
| supplyTotalTemperature 300; | |
| plenumVolume 0.000125; | |
| plenumDensity 1.1613; | |
| plenumTemperature 300; | |
| inletAreaRatio 1.0; | |
| inletDischargeCoefficient 0.8; | |
| timeScale 1e-4; | |
| value uniform 1e5; | |
| } | |
| \endverbatim | |
| SourceFiles | |
| plenumPressureFvPatchScalarField.C | |
| \*---------------------------------------------------------------------------*/ | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| namespace Foam | |
| { | |
| /*---------------------------------------------------------------------------*\ | |
| Class plenumPressureFvPatch Declaration | |
| \*---------------------------------------------------------------------------*/ | |
| class plenumPressureFvPatchScalarField | |
| : | |
| public fixedValueFvPatchScalarField | |
| { | |
| // Private Data | |
| //- Ratio of specific heats | |
| scalar gamma_; | |
| //- Specific gas constant | |
| scalar R_; | |
| //- Mass flow rate supplied to the plenum | |
| scalar supplyMassFlowRate_; | |
| //- Total temperature of the gas supplied to the plenum | |
| scalar supplyTotalTemperature_; | |
| //- The volume of the plenum | |
| scalar plenumVolume_; | |
| //- The mean density of the gas in the plenum | |
| scalar plenumDensity_; | |
| //- The old-time mean density of the gas in the plenum | |
| scalar plenumDensityOld_; | |
| //- The mean temperature of the gas in the plenum | |
| scalar plenumTemperature_; | |
| //- The mean old-time temperature of the gas in the plenum | |
| scalar plenumTemperatureOld_; | |
| //- The constant density used when phi is volumetric | |
| scalar rho_; | |
| //- Whether or not the constant density has been specified | |
| bool hasRho_; | |
| //- The ratio of open area to total area at the inlet | |
| // Allows a grid or mesh to be represented | |
| scalar inletAreaRatio_; | |
| //- The discharge coefficient at the inlet | |
| scalar inletDischargeCoefficient_; | |
| //- The time scale over which changes in pressure are smoothed | |
| scalar timeScale_; | |
| //- The time index used for updating | |
| label timeIndex_; | |
| //- The name of the flux field | |
| word phiName_; | |
| //- The name of the velocity field | |
| word UName_; | |
| public: | |
| //- Runtime type information | |
| TypeName("plenumPressure"); | |
| // Constructors | |
| //- Construct from patch, internal field and dictionary | |
| plenumPressureFvPatchScalarField | |
| ( | |
| const fvPatch&, | |
| const DimensionedField<scalar, fvMesh>&, | |
| const dictionary& | |
| ); | |
| //- Construct by mapping given plenumPressureFvPatchScalarField | |
| // onto a new patch | |
| plenumPressureFvPatchScalarField | |
| ( | |
| const plenumPressureFvPatchScalarField&, | |
| const fvPatch&, | |
| const DimensionedField<scalar, fvMesh>&, | |
| const fieldMapper& | |
| ); | |
| //- Disallow copy without setting internal field reference | |
| plenumPressureFvPatchScalarField | |
| ( | |
| const plenumPressureFvPatchScalarField& | |
| ) = delete; | |
| //- Copy constructor setting internal field reference | |
| plenumPressureFvPatchScalarField | |
| ( | |
| const plenumPressureFvPatchScalarField&, | |
| const DimensionedField<scalar, fvMesh>& | |
| ); | |
| //- Construct and return a clone setting internal field reference | |
| virtual tmp<fvPatchScalarField> clone | |
| ( | |
| const DimensionedField<scalar, fvMesh>& iF | |
| ) const | |
| { | |
| return tmp<fvPatchScalarField> | |
| ( | |
| new plenumPressureFvPatchScalarField(*this, iF) | |
| ); | |
| } | |
| // Member Functions | |
| // Evaluation functions | |
| //- Update the coefficients associated with the patch field | |
| virtual void updateCoeffs(); | |
| //- Write | |
| virtual void write(Ostream&) const; | |
| // Member Operators | |
| //- Inherit assignment | |
| using fixedValueFvPatchScalarField::operator=; | |
| }; | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| } // End namespace Foam | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| // ************************************************************************* // | |