/*---------------------------------------------------------------------------*\
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    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
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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 <http://www.gnu.org/licenses/>.

Application
    writeEk

Description
    This function evaluates q(k) (McComb, p61) by summing all wavevectors
    in a k-shell. Then we divide through by the volume of the box
    - to be accurate, by the volume of the ellipsoid enclosing the
    box (assume cells even in each direction). Finally, multiply the
    q(k) values by k^2 to give the full power spectrum E(k). Integrating
    this over the whole range gives the energy in turbulence.

\*---------------------------------------------------------------------------*/

#ifndef writeEk_H
#define writeEk_H

#include "volFieldsFwd.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

class Kmesh;

void writeEk
(
    const volVectorField& U,
    const Kmesh& K
);


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //