From 94d3e79a8617f88dc0219cfdeedfa3147833719d Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 24 Jun 2019 14:43:36 +0200
Subject: Initialize at openlb-1-3

---
 src/dynamics/stochasticSGSdynamics.h | 102 +++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 src/dynamics/stochasticSGSdynamics.h

(limited to 'src/dynamics/stochasticSGSdynamics.h')

diff --git a/src/dynamics/stochasticSGSdynamics.h b/src/dynamics/stochasticSGSdynamics.h
new file mode 100644
index 0000000..8cff605
--- /dev/null
+++ b/src/dynamics/stochasticSGSdynamics.h
@@ -0,0 +1,102 @@
+/*  This file is part of the OpenLB library
+ *
+ *  Copyright (C) 2013 Patrick Nathen
+ *  E-mail contact: info@openlb.net
+ *  The most recent release of OpenLB can be downloaded at
+ *  <http://www.openlb.net/>
+ *
+ *  This program 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 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program 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 this program; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA  02110-1301, USA.
+*/
+
+/** \file
+ * MRT Dynamics with adjusted omega -- header file.
+ */
+#ifndef STOCHASTIC_SGS_DYNAMICS_H
+#define STOCHASTIC_SGS_DYNAMICS_H
+
+#include "mrtDynamics.h"
+#include "core/cell.h"
+
+
+namespace olb {
+
+/// Implementation of the MRT collision step with stochastic relaxation based on
+/// " A stochastic subgrid model with application to turbulent flow and scalar mixing"; Phys. of Fluids 19; 2007
+template<typename T, typename DESCRIPTOR>
+class StochasticSGSdynamics : public MRTdynamics<T,DESCRIPTOR> {
+public:
+  /// Constructor
+  StochasticSGSdynamics(T omega_, Momenta<T,DESCRIPTOR>& momenta_, T turbulenceInt_, T charU_, T smagoConst_, T dx_ = 1, T dt_ = 1 );
+
+
+  // Collide
+  virtual void collide(Cell<T,DESCRIPTOR>& cell,
+                       LatticeStatistics<T>& statistics_);
+
+  /// Set local relaxation parameter of the dynamics
+  virtual void setOmega(T omega_);
+
+  /// Get local smagorinsky relaxation parameter of the dynamics
+  virtual T getSmagorinskyOmega(Cell<T,DESCRIPTOR>& cell_, T X_lang_n_);
+
+  /// Get local Random number of BoxMüllertransform -> returns randBM
+  virtual T getRandBMTrans(Cell<T,DESCRIPTOR>& cell_,  T turbulenceInt_, T charU_);
+
+  /// Get local Random number of BoxMüllertransform -> returns randBM
+  // virtual void setRandomWalk(Cell<T,DESCRIPTOR>& cell_, T CharU, T drift_, T result_ );
+  virtual T getRandomWalk(Cell<T,DESCRIPTOR>& cell_, T drift_, T result_);
+
+
+private:
+  /// Computes a constant prefactor in order to speed up the computation
+  T computePreFactor(T omega_, T smagoConst_);
+
+  /// Computes the local smagorinsky relaxation parameter
+  T computeOmega(T omega0_, T preFactor_, T rho_, T pi_[util::TensorVal<DESCRIPTOR >::n] , T X_lang_n_);
+
+  /// Computes the local time scale from SGS dissipation rate for BMtransform
+  T computeTimeScale(T preFactor_, T rho_, T pi_[util::TensorVal<DESCRIPTOR >::n], T smagoConst_, T X_lang_n_);
+  // virtual void setTimeScale(T preFactor_, T rho_, T pi_[util::TensorVal<DESCRIPTOR >::n], T smagoConst_ ,T X_lang_n_);
+
+private:
+  /// effective collision time based upon Smagorisnky approach
+  T tau_eff;
+  /// Initial turbulence intensity for random number generator
+  T turbulenceInt;
+  /// Smagorinsky Constant
+  /// Precomputed constant which speeeds up the computation
+  T smagoConst;
+  T preFactor;
+
+  T dx;
+  T dt;
+
+  T omega; // the shear viscosity relaxatin time
+  T lambda;// the bulk viscosity relaxatin time
+
+  //T result;
+  T charU;
+  //T drift;
+  T X_lang_n;
+
+  // Relaxation Time Matrix for
+  T invM_S_SGS[DESCRIPTOR::q][DESCRIPTOR::q];
+
+};
+
+}
+
+#endif
-- 
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