| /*---------------------------------------------------------------------------*\ | |
| ========= | | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | |
| \\ / O peration | Website: https://openfoam.org | |
| \\ / A nd | Copyright (C) 2012-2025 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. | |
| OpenFOAM is distributed in the hope that it will be useful, but WITHOUT | |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 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::functionObjects::pressure | |
| Description | |
| Includes tools to manipulate the pressure into different forms. | |
| These currently include: | |
| - static pressure | |
| \f[ | |
| p = \rho p_k | |
| \f] | |
| - total pressure | |
| \f[ | |
| p_0 = p_{ref} + p + 0.5 \rho |U|^2 | |
| \f] | |
| - static pressure coefficient | |
| \f[ | |
| Cp = \frac{p - p_{\inf}}{0.5 \rho_{\inf} |U_{\inf}|^2} | |
| \f] | |
| - total pressure coefficient | |
| \f[ | |
| Cp_0 = \frac{p_0 - p_{\inf}}{0.5 \rho_{\inf} |U_{\inf}|^2} | |
| \f] | |
| where | |
| \vartable | |
| \rho | Density [kg/m^3] | |
| U | Velocity [m/s] | |
| \rho_{\inf} | Freestream density [kg/m^3] | |
| p_{\inf} | Freestream pressure [Pa] | |
| U_{\inf} | Freestream velocity [m/s] | |
| p_k | Kinematic pressure (p/rho) [m^2/s^2] | |
| p | Pressure [Pa] | |
| p_0 | Total pressure [Pa] | |
| p_{ref} | Reference pressure level [Pa] | |
| Cp | Pressure coefficient | |
| Cp_0 | Total pressure coefficient | |
| \endvartable | |
| The function object will operate on both kinematic (\f$ p_k \f$) and static | |
| pressure (\f$ p \f$) fields, and the result is written as a | |
| volScalarField. | |
| The modes of operation are: | |
| \table | |
| Mode | calcTotal | calcCoeff | |
| Static pressure | no | no | |
| Total pressure | yes | no | |
| Pressure coefficient | no | yes | |
| Total pressure coefficient | yes | yes | |
| \endtable | |
| Example of function object specification to calculate pressure coefficient: | |
| \verbatim | |
| pressure1 | |
| { | |
| type pressure; | |
| libs ("libfieldFunctionObjects.so"); | |
| ... | |
| calcTotal no; | |
| calcCoeff yes; | |
| } | |
| \endverbatim | |
| Usage | |
| \table | |
| Property | Description | Required | Default value | |
| type | type name: pressure | yes | | |
| field | Name of the pressure field | no | p | |
| U | Name of the velocity field | no | U | |
| rho | Name of the density field | no | rho | |
| result | Name of the resulting field | no | derived from p | |
| calcTotal | Calculate total coefficient | yes | | |
| pRef | Reference pressure for total pressure | no | 0 | |
| calcCoeff | Calculate pressure coefficient | yes | | |
| pInf | Freestream pressure for coefficient calculation | no | | |
| UInf | Freestream velocity for coefficient calculation | no | | |
| rhoInf | Freestream density for coefficient calculation | no | | |
| \endtable | |
| See also | |
| Foam::functionObjects::fieldExpression | |
| Foam::functionObjects::fvMeshFunctionObject | |
| SourceFiles | |
| pressure.C | |
| \*---------------------------------------------------------------------------*/ | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| namespace Foam | |
| { | |
| namespace functionObjects | |
| { | |
| /*---------------------------------------------------------------------------*\ | |
| Class pressure Declaration | |
| \*---------------------------------------------------------------------------*/ | |
| class pressure | |
| : | |
| public fieldExpression | |
| { | |
| // Private Data | |
| //- Name of velocity field, default is "U" | |
| word UName_; | |
| //- Name of density field, default is "rho" | |
| word rhoName_; | |
| // Total pressure calculation | |
| //- Flag to calculate total pressure | |
| bool calcTotal_; | |
| //- Reference pressure level | |
| scalar pRef_; | |
| // Pressure coefficient calculation | |
| //- Flag to calculate pressure coefficient | |
| bool calcCoeff_; | |
| //- Freestream pressure | |
| scalar pInf_; | |
| //- Freestream velocity | |
| vector UInf_; | |
| //- Freestream density | |
| scalar rhoInf_; | |
| // Private Member Functions | |
| //- Return the name of the derived pressure field | |
| word resultName() const; | |
| //- Multiply the static pressure p by rhoInf if necessary and return | |
| tmp<volScalarField> rhoScale(const volScalarField& p) const; | |
| //- Multiply the given field by rho or rhoInf as appropriate and return | |
| tmp<volScalarField> rhoScale | |
| ( | |
| const volScalarField& p, | |
| const tmp<volScalarField>& tsf | |
| ) const; | |
| //- Return the reference pressure | |
| tmp<volScalarField> pRef(const tmp<volScalarField>& tp) const; | |
| //- Calculate and return the dynamic pressure | |
| tmp<volScalarField> pDyn | |
| ( | |
| const volScalarField& p, | |
| const tmp<volScalarField>& tp | |
| ) const; | |
| //- Convert to coeff by applying the freestream dynamic pressure scaling | |
| tmp<volScalarField> coeff(const tmp<volScalarField>& tp) const; | |
| //- Calculate the derived pressure field and return true if successful | |
| virtual bool calc(); | |
| public: | |
| //- Runtime type information | |
| TypeName("pressure"); | |
| // Constructors | |
| //- Construct from Time and dictionary | |
| pressure | |
| ( | |
| const word& name, | |
| const Time& runTime, | |
| const dictionary& | |
| ); | |
| //- Destructor | |
| virtual ~pressure(); | |
| // Member Functions | |
| //- Read the pressure data | |
| virtual bool read(const dictionary&); | |
| }; | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| } // End namespace functionObjects | |
| } // End namespace Foam | |
| // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // | |
| // ************************************************************************* // | |