path: root/src/dynamics/dynamics.h

/*  This file is part of the OpenLB library
 *
 *  Copyright (C) 2006, 2007 Jonas Latt, Mathias J. Krause
 *  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
 * A collection of dynamics classes (e.g. BGK) with which a Cell object
 * can be instantiated -- header file.
 */
#ifndef LB_DYNAMICS_H
#define LB_DYNAMICS_H

#include "latticeDescriptors.h"
#include "core/util.h"
#include "core/postProcessing.h"
#include "core/latticeStatistics.h"

namespace olb {


template<typename T, typename DESCRIPTOR> class Cell;

/// Interface for the dynamics classes
template<typename T, typename DESCRIPTOR>
struct Dynamics {
  /// Destructor: virtual to enable inheritance
  virtual ~Dynamics() { }
  /// Implementation of the collision step
  virtual void collide(Cell<T,DESCRIPTOR>& cell,
                       LatticeStatistics<T>& statistics_) =0;
  /// Compute equilibrium distribution function
  virtual T computeEquilibrium(int iPop, T rho, const T u[DESCRIPTOR::d], T uSqr) const;
  /// Initialize cell at equilibrium distribution
  void iniEquilibrium(Cell<T,DESCRIPTOR>& cell, T rho, const T u[DESCRIPTOR::d]);
  /// Compute particle density on the cell.
  /** \return particle density
   */
  virtual T computeRho(Cell<T,DESCRIPTOR> const& cell) const =0;
  /// Compute fluid velocity on the cell.
  /** \param u fluid velocity
   */
  virtual void computeU( Cell<T,DESCRIPTOR> const& cell,
                         T u[DESCRIPTOR::d] ) const =0;
  /// Compute fluid momentum (j=rho*u) on the cell.
  /** \param j fluid momentum
   */
  virtual void computeJ( Cell<T,DESCRIPTOR> const& cell,
                         T j[DESCRIPTOR::d] ) const =0;
  /// Compute components of the stress tensor on the cell.
  /** \param pi stress tensor */
  virtual void computeStress (
    Cell<T,DESCRIPTOR> const& cell,
    T rho, const T u[DESCRIPTOR::d],
    T pi[util::TensorVal<DESCRIPTOR >::n] ) const =0;
  /// Compute fluid velocity and particle density on the cell.
  /** \param rho particle density
   *  \param u fluid velocity
   */
  virtual void computeRhoU (
    Cell<T,DESCRIPTOR> const& cell,
    T& rho, T u[DESCRIPTOR::d]) const =0;
  /// Compute all momenta on the cell, up to second order.
  /** \param rho particle density
   *  \param u fluid velocity
   *  \param pi stress tensor
   */
  virtual void computeAllMomenta (
    Cell<T,DESCRIPTOR> const& cell,
    T& rho, T u[DESCRIPTOR::d],
    T pi[util::TensorVal<DESCRIPTOR >::n] ) const =0;
  /// Set particle density on the cell.
  /** \param rho particle density
   */
  virtual void defineRho(Cell<T,DESCRIPTOR>& cell, T rho) =0;
  virtual void defineRho(int iPop, T rho);
  /// Set fluid velocity on the cell.
  /** \param u fluid velocity
   */
  virtual void defineU(Cell<T,DESCRIPTOR>& cell,
                       const T u[DESCRIPTOR::d]) =0;
  /// Functions for offLattice Velocity boundary conditions
  virtual void setBoundaryIntersection(int iPop, T distance);
  virtual bool getBoundaryIntersection(int iPop, T point[DESCRIPTOR::d]);
  virtual void defineU(const T u[DESCRIPTOR::d]);
  virtual void defineU(int iPop, const T u[DESCRIPTOR::d]);
  virtual T    getVelocityCoefficient(int iPop);

  /// Define fluid velocity and particle density on the cell.
  /** \param rho particle density
   *  \param u fluid velocity
   */
  virtual void defineRhoU (
    Cell<T,DESCRIPTOR>& cell,
    T rho, const T u[DESCRIPTOR::d]) =0;
  /// Define all momenta on the cell, up to second order.
  /** \param rho particle density
   *  \param u fluid velocity
   *  \param pi stress tensor
   */
  virtual void defineAllMomenta (
    Cell<T,DESCRIPTOR>& cell,
    T rho, const T u[DESCRIPTOR::d],
    const T pi[util::TensorVal<DESCRIPTOR >::n] ) =0;
  /// Get local relaxation parameter of the dynamics
  virtual T getOmega() const =0;
  /// Set local relaxation parameter of the dynamics
  virtual void setOmega(T omega) =0;
};

/// Interface for classes that compute velocity momenta
/** This class is useful for example to distinguish between bulk and
<