/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | www.openfoam.com
\\/ M anipulation |
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Copyright (C) 2011-2016 OpenFOAM Foundation
Copyright (C) 2019 OpenCFD Ltd.
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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 .
Class
Foam::functionObjects::forceCoeffs
Group
grpForcesFunctionObjects
Description
Extends the \c forces functionObject by providing coefficients for:
- drag, side and lift forces (Cd, Cs, and Cl)
- roll, pitch and yaw moments (CmRoll, CmPitch, and CmYaw)
- front and rear axle force contributions (C(f) and C(r)) wherein
\verbatim
Cd(f/r) = 0.5*Cd \pm CmRoll
Cs(f/r) = 0.5*Cs \pm CmYaw
Cl(f/r) = 0.5*Cl \pm CmPitch
\endverbatim
The data can optionally be output into bins, defined in a given direction.
The binned data provides the total and consitituent components per bin:
- total coefficient
- pressure coefficient contribution
- viscous coefficient contribution
- porous coefficient contribution
Data is written into multiple files in the
postProcessing/\ directory:
- coefficient.dat : integrated coefficients over all geometries
- CdBin.dat : drag coefficient bins
- CsBin.dat : side coefficient bins
- ClBin.dat : lift coefficient bins
- CmRollBin.dat : roll moment coefficient bins
- CmPitchBin.dat : pitch moment coefficient bins
- CmYawBin.dat : yaw moment coefficient bins
Usage
Example of function object specification:
\verbatim
forceCoeffs1
{
type forceCoeffs;
libs ("libforces.so");
...
log yes;
writeFields yes;
patches (walls);
// input keywords for directions of force/moment coefficients
// refer below for options, and relations
magUInf 100;
lRef 3.5;
Aref 2.2;
porosity no;
binData
{
nBin 20;
direction (1 0 0);
cumulative yes;
}
}
\endverbatim
Where the entries comprise:
\table
Property | Description | Required | Default
type | Type name: forceCoeffs | yes |
log | Write force data to standard output | no | no
writeFields | Write force,moment coefficient fields | no | no
patches | Patches included in the forces calculation | yes |
magUInf | Free stream velocity magnitude | yes |
rhoInf | Free stream density | for compressible cases |
lRef | Reference length scale for moment calculations | yes |
Aref | Reference area | yes |
porosity | Include porosity contributions | no | false
\endtable
Bin data is optional, but if the dictionary is present, the entries must
be defined according to following:
\table
nBin | Number of data bins | yes |
direction | Direction along which bins are defined | yes |
cumulative | Bin data accumulated with incresing distance | yes |
\endtable
Input of force/moment coefficient directions:
- require an origin, and two orthogonal directions; the remaining orthogonal
direction is determined accordingly.
- can be added by the three options below.
\verbatim
CofR (0 0 0); // Centre of rotation
dragDir (1 0 0);
liftDir (0 0 1);
\endverbatim
\verbatim
origin (0 0 0);
e1 (1 0 0);
e3 (0 0 1); // combinations: (e1, e2) or (e2, e3) or (e3, e1)
\endverbatim
\verbatim
coordinateSystem
{
origin (0 0 0);
rotation
{
type axes;
e1 (1 0 0);
e3 (0 0 1); // combinations: (e1, e2) or (e2, e3) or (e3, e1)
}
}
\endverbatim
The default direction relations are shown below:
\table
Property | Description | Alias | Direction
dragDir | Drag direction | e1 | (1 0 0)
sideDir | Side force direction | e2 | (0 1 0)
liftDir | Lift direction | e3 | (0 0 1)
rollAxis | Roll axis | e1 | (1 0 0)
pitchAxis | Pitch axis | e2 | (0 1 0)
yawAxis | Yaw axis | e3 | (0 0 1)
\endtable
See also
Foam::functionObject
Foam::functionObjects::timeControl
Foam::functionObjects::forces
SourceFiles
forceCoeffs.C
\*---------------------------------------------------------------------------*/
#ifndef functionObjects_forceCoeffs_H
#define functionObjects_forceCoeffs_H
#include "forces.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace functionObjects
{
/*---------------------------------------------------------------------------*\
Class forceCoeffs Declaration
\*---------------------------------------------------------------------------*/
class forceCoeffs
:
public forces
{
// Private data
// Free-stream conditions
//- Free-stream velocity magnitude
scalar magUInf_;
// Reference scales
//- Reference length [m]
scalar lRef_;
//- Reference area [m^2]
scalar Aref_;
// File streams
//- Integrated coefficients
autoPtr coeffFilePtr_;
//- Drag coefficient
autoPtr CdBinFilePtr_;
//- Side coefficient
autoPtr CsBinFilePtr_;
//- Lift coefficient
autoPtr ClBinFilePtr_;
//- Roll moment coefficient
autoPtr CmRollBinFilePtr_;
//- Pitch moment coefficient
autoPtr CmPitchBinFilePtr_;
//- Yaw moment coefficient
autoPtr CmYawBinFilePtr_;
// Private Member Functions
//- No copy construct
forceCoeffs(const forceCoeffs&) = delete;
//- No copy assignment
void operator=(const forceCoeffs&) = delete;
protected:
// Protected Member Functions
//- Create the output files
void createFiles();
//- Write header for integrated data
void writeIntegratedHeader(const word& header, Ostream& os) const;
//- Write header for binned data
void writeBinHeader(const word& header, Ostream& os) const;
//- Write integrated data
void writeIntegratedData
(
const word& title,
const List>& coeff
) const;
//- Write binned data
void writeBinData(const List> coeffs, Ostream& os) const;
public:
//- Runtime type information
TypeName("forceCoeffs");
// Constructors
//- Construct from Time and dictionary
forceCoeffs
(
const word& name,
const Time& runTime,
const dictionary&,
const bool readFields = true
);
//- Destructor
virtual ~forceCoeffs() = default;
// Member Functions
//- Read the forces data
virtual bool read(const dictionary&);
//- Execute
virtual bool execute();
//- Write the forces
virtual bool write();
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace functionObjects
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //