src/lagrangian/dieselSpray/spraySubModels/dispersionModel/stochasticDispersionRAS/stochasticDispersionRAS.C

   1 /*---------------------------------------------------------------------------*\
   2   =========                 |
   3   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   4    \\    /   O peration     |
   5     \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
   6      \\/     M anipulation  |
   7 -------------------------------------------------------------------------------
   8 License
   9     This file is part of OpenFOAM.
  10
  11     OpenFOAM is free software: you can redistribute it and/or modify it
  12     under the terms of the GNU General Public License as published by
  13     the Free Software Foundation, either version 3 of the License, or
  14     (at your option) any later version.
  15
  16     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
  17     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  19     for more details.
  20
  21     You should have received a copy of the GNU General Public License
  22     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 \*---------------------------------------------------------------------------*/
  25
  26 #include "error.H"
  27
  28 #include "stochasticDispersionRAS.H"
  29 #include "addToRunTimeSelectionTable.H"
  30
  31 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
  32
  33 namespace Foam
  34 {
  35     defineTypeNameAndDebug(stochasticDispersionRAS, 0);
  36
  37     addToRunTimeSelectionTable
  38     (
  39         dispersionModel,
  40         stochasticDispersionRAS,
  41         dictionary
  42     );
  43 }
  44
  45
  46 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
  47
  48 Foam::stochasticDispersionRAS::stochasticDispersionRAS
  49 (
  50     const dictionary& dict,
  51     spray& sm
  52 )
  53 :
  54     dispersionRASModel(dict, sm)
  55 {}
  56
  57
  58 // * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
  59
  60 Foam::stochasticDispersionRAS::~stochasticDispersionRAS()
  61 {}
  62
  63
  64 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
  65
  66 void Foam::stochasticDispersionRAS::disperseParcels() const
  67 {
  68
  69     const scalar cps = 0.16432;
  70     const vector one(1.0, 1.0, 1.0);
  71
  72     scalar dt = spray_.runTime().deltaTValue();
  73     const volScalarField& k = turbulence().k();
  74     // volVectorField gradk(fvc::grad(k));
  75     const volScalarField& epsilon = turbulence().epsilon();
  76     const volVectorField& U = spray_.U();
  77
  78     forAllIter(spray, spray_, elmnt)
  79     {
  80         const label cellI = elmnt().cell();
  81         scalar UrelMag = mag(elmnt().U() - U[cellI] - elmnt().Uturb());
  82
  83         scalar Tturb = min
  84         (
  85             k[cellI]/epsilon[cellI],
  86             cps*pow(k[cellI], 1.5)/epsilon[cellI]/(UrelMag + SMALL)
  87         );
  88
  89         // parcel is perturbed by the turbulence
  90         if (dt < Tturb)
  91         {
  92             elmnt().tTurb() += dt;
  93
  94             if (elmnt().tTurb() > Tturb)
  95             {
  96                 elmnt().tTurb() = 0.0;
  97
  98                 scalar sigma = sqrt(2.0*k[cellI]/3.0);
  99                 vector dir = 2.0*spray_.rndGen().sample01<vector>() - one;
 100                 dir /= mag(dir) + SMALL;
 101
 102                 // numerical recipes... Ch. 7. Random Numbers...
 103                 scalar x1,x2;
 104                 scalar rsq = 10.0;
 105                 while (rsq > 1.0 || rsq == 0.0)
 106                 {
 107                     x1 = 2.0*spray_.rndGen().sample01<scalar>() - 1.0;
 108                     x2 = 2.0*spray_.rndGen().sample01<scalar>() - 1.0;
 109                     rsq = x1*x1 + x2*x2;
 110                 }
 111
 112                 scalar fac = sqrt(-2.0*log(rsq)/rsq);
 113
 114                 fac *= mag(x1);
 115
 116                 elmnt().Uturb() = sigma*fac*dir;
 117
 118             }
 119         }
 120         else
 121         {
 122             elmnt().tTurb() = GREAT;
 123             elmnt().Uturb() = vector::zero;
 124         }
 125     }
 126 }
 127
 128
 129 // ************************************************************************* //