targetCoeffTrim.H

Go to the documentation of this file.

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2012-2014 OpenFOAM Foundation
-------------------------------------------------------------------------------
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::targetCoeffTrim
 
Description
    Target trim forces/coefficients
 
    Solves:
 
        c^old + J.d(theta) = c^target
 
    Where:
 
        n     = time level
        c     = coefficient vector (thrust force, roll moment, pitch moment)
        theta = pitch angle vector (collective, roll, pitch)
        J     = Jacobian [3x3] matrix
 
 
    The trimmed pitch angles are found via solving the above with a
    Newton-Raphson iterative method.  The solver tolerance can be user-input,
    using the 'tol' entry.
 
    If coefficients are requested (useCoeffs = true), the force and moments
    are normalised using:
 
                         force
        c = ---------------------------------
            alpha*pi*rho*(omega^2)*(radius^4)
 
    and
 
                         moment
        c = ---------------------------------
            alpha*pi*rho*(omega^2)*(radius^5)
 
    Where:
 
        alpha = user-input conversion coefficient (default = 1)
        rho   = desity
        omega = rotor angulr velocity
        pi    = mathematical pi
 
 
SourceFiles
    targetCoeffTrim.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef targetCoeffTrim_H
#define targetCoeffTrim_H
 
#include "trimModel.H"
#include "tensor.H"
#include "vector.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                      Class targetCoeffTrim Declaration
\*---------------------------------------------------------------------------*/
 
class targetCoeffTrim
:
    public trimModel
{
protected:
 
    // Protected data
 
        //- Number of iterations between calls to 'correct'
        label calcFrequency_;
 
        //- Flag to indicate whether to solve coeffs (true) or forces (false)
        bool useCoeffs_;
 
        //- Target coefficient vector (thrust force, roll moment, pitch moment)
        vector target_;
 
        //- Pitch angles (collective, roll, pitch) [rad]
        vector theta_;
 
        //- Maximum number of iterations in trim routine
        label nIter_;
 
        //- Convergence tolerance
        scalar tol_;
 
        //- Under-relaxation coefficient
        scalar relax_;
 
        //- Perturbation angle used to determine jacobian
        scalar dTheta_;
 
        //- Coefficient to allow for conversion between US and EU definitions
        scalar alpha_;
 
 
    // Protected member functions
 
        //- Calculate the rotor force and moment coefficients vector
        template<class RhoFieldType>
        vector calcCoeffs
        (
            const RhoFieldType& rho,
            const vectorField& U,
            const scalarField& alphag,
            vectorField& force
        ) const;
 
        //- Correct the model
        template<class RhoFieldType>
        void correctTrim
        (
            const RhoFieldType& rho,
            const vectorField& U,
            vectorField& force
        );
 
 
public:
 
    //- Run-time type information
    TypeName("targetCoeffTrim");
 
    //- Constructor
    targetCoeffTrim(const fv::rotorDiskSource& rotor, const dictionary& dict);
 
    //- Destructor
    virtual ~targetCoeffTrim() = default;
 
 
    // Member Functions
 
        //- Read
        void read(const dictionary& dict);
 
        //- Return the geometric angle of attack [rad]
        virtual tmp<scalarField> thetag() const;
 
        //- Correct the model
        virtual void correct
        (
            const vectorField& U,
            vectorField& force
        );
 
        //- Correct the model for compressible flow
        virtual void correct
        (
            const volScalarField rho,
            const vectorField& U,
            vectorField& force
        );
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //