Initialize at openlb-1-3

10 files changed, 1772 insertions, 0 deletions

diff --git a/src/particles/twoWayCouplings/backCouplingModels.h b/src/particles/twoWayCouplings/backCouplingModels.h
new file mode 100644
index 0000000..8f016d2
--- /dev/null
+++ b/src/particles/twoWayCouplings/backCouplingModels.h
@@ -0,0 +1,124 @@
+/*  Lattice Boltzmann sample, written in C++, using the OpenLB
+ *  library
+ *
+ *  Copyright (C) 2019 Davide Dapelo
+ *  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.
+ */
+
+/* Models for Lagrangian back-coupling methods -- header file.
+ */
+
+#ifndef LB_BACK_COUPLING_MODELS_H
+#define LB_BACK_COUPLING_MODELS_H
+
+#include "twoWayHelperFunctionals.h"
+
+namespace olb {
+
+/** Abstact base class for BaseBackCouplingModel.
+  * Its raison d'etre consists of not being templetized in Lattice.
+  */
+template<typename T, template<typename V> class Particle>
+class BackCouplingModel {
+public:
+  /// Class operator to apply the coupling, for overload.
+  virtual bool operator() (Particle<T>* p, int globic, int material, int subCycles=1)=0;
+  /// Resets external field
+  virtual void resetExternalField(int material)=0;
+};
+
+/** Abstact class for all the back-coupling models,
+  * viz., momentum coupling from particle to fluid.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class BaseBackCouplingModel : public BackCouplingModel<T,Particle> {
+public:
+  /// Resets external field
+  virtual void resetExternalField(int material) override;
+protected:
+  /// Constructor
+  BaseBackCouplingModel ( UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry );
+  UnitConverter<T, Lattice>& _converter; // reference to a UnitConverter
+  SuperGeometry3D<T>& _sGeometry;
+  SuperLattice3D<T, Lattice>& _sLattice; // reference to a lattice
+private:
+  // Pointers to functions to reset fluid force
+  std::shared_ptr<AnalyticalConst3D<T, T> > _zeroAnalytical;
+  std::shared_ptr<AnalyticalComposed3D<T, T> > _zeroField;
+};
+
+/** Back-coupling is performed on the cell containing the particle
+  * and its neighbours within a cube of one lattice spacing, as per in Maier et al. (2017).
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class CubicDeltaBackCouplingModel : public BaseBackCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  CubicDeltaBackCouplingModel ( UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry );
+  /// Class operator to apply the coupling.
+  virtual bool operator() (Particle<T>* p, int globic, int material, int subCycles=1) override;
+protected:
+  int _range = 1;
+  T _delta[4][4][4] = { T() };
+  std::shared_ptr<SuperLatticeSmoothDiracDelta3D<T, Lattice> > _cubicDeltaFunctional;
+};
+
+/** Back-coupling is performed only on the cell containing the particle.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class LocalBackCouplingModel : public BaseBackCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  LocalBackCouplingModel ( UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry );
+  /// Class operator to apply the coupling.
+  virtual bool operator() (Particle<T>* p, int globic, int material, int subCycles=1) override;
+};
+
+/** Class for a generic non-local back-coupling model,
+  * viz., momentum coupling from particle to fluid.
+  * It reproduces the characteristics (viz., smoothing) of an input forward coupling model.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class NonLocalBaseBackCouplingModel : public BaseBackCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  NonLocalBaseBackCouplingModel ( UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry,
+                         SmoothingFunctional<T, Lattice>& smoothingFunctional );
+  /// Class operator to apply the coupling.
+  virtual bool operator() (Particle<T>* p, int globic, int material, int subCycles=1) override;
+protected:
+  SmoothingFunctional<T, Lattice>& _smoothingFunctional; // Functional to treat non-local smoothing
+};
+
+}
+
+#endif
diff --git a/src/particles/twoWayCouplings/backCouplingModels.hh b/src/particles/twoWayCouplings/backCouplingModels.hh
new file mode 100644
index 0000000..e88c62a
--- /dev/null
+++ b/src/particles/twoWayCouplings/backCouplingModels.hh
@@ -0,0 +1,230 @@
+/*  Lattice Boltzmann sample, written in C++, using the OpenLB
+ *  library
+ *
+ *  Copyright (C) 2019 Davide Dapelo
+ *  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.
+ */
+
+/* Models for Lagrangian back-coupling methods -- generic implementation.
+ */
+
+#ifndef LB_BACK_COUPLING_MODELS_HH
+#define LB_BACK_COUPLING_MODELS_HH
+
+namespace olb {
+
+
+////////////////////// Class BaseBackCouplingModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+BaseBackCouplingModel<T,Lattice,Particle>::BaseBackCouplingModel (
+                 UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry )
+         : _converter(converter),
+           _sGeometry(sGeometry),
+           _sLattice(sLattice)
+{
+  _zeroAnalytical = std::make_shared<AnalyticalConst3D<T, T> > (T());
+  _zeroField = std::make_shared<AnalyticalComposed3D<T, T> > (*_zeroAnalytical, *_zeroAnalytical, *_zeroAnalytical);
+}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+void BaseBackCouplingModel<T,Lattice,Particle>::resetExternalField(int material)
+{
+  // resets external field
+  this->_sLattice.template defineField<descriptors::FORCE>(this->_sGeometry, material, *_zeroField);
+
+  // NECESSARY to communicate values before using them in operator()
+  this->_sLattice.communicate();
+}
+
+
+////////////////////// Class CubicDeltaBackCouplingModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+CubicDeltaBackCouplingModel<T,Lattice,Particle>::CubicDeltaBackCouplingModel (
+                 UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry )
+         : BaseBackCouplingModel<T,Lattice,Particle>(converter, sLattice, sGeometry)
+{
+  _cubicDeltaFunctional = std::make_shared<SuperLatticeSmoothDiracDelta3D<T, Lattice> > (
+      this->_sLattice, this->_converter, this->_sGeometry );
+}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+bool CubicDeltaBackCouplingModel<T,Lattice,Particle>::operator() (Particle<T>* p, int globic, int material, int subCycles)
+{
+  int locIC = this->_sLattice.getLoadBalancer().loc(globic);
+
+  // reading the force from the value stored inside the particle
+  std::vector<T> physForceP = p->getStoreForce(); // physical force acting on the particle
+
+  T latticeForceP[3] = {T(), T(), T()}; // dimensionless force acting on the particle
+  latticeForceP[0] = physForceP[0] / this->_converter.getConversionFactorForce();
+  latticeForceP[1] = physForceP[1] / this->_converter.getConversionFactorForce();
+  latticeForceP[2] = physForceP[2] / this->_converter.getConversionFactorForce();
+
+  T physPosP[3] = {T(), T(), T()}; // particle's physical position
+  physPosP[0] = (p->getPos()[0]);
+  physPosP[1] = (p->getPos()[1]);
+  physPosP[2] = (p->getPos()[2]);
+
+  // particle's dimensionless position, rounded at neighbouring voxel
+  int latticeRoundedPosP[3] = {0, 0, 0};
+  this->_sLattice.getCuboidGeometry().get(globic).getLatticeR (
+           latticeRoundedPosP, physPosP );
+
+  // smooth Dirac delta
+  this->_cubicDeltaFunctional->operator() (_delta, physPosP, globic);
+
+  T tempDelta = T();
+  T F[3] = {T(), T(), T()}; // dimensionless smoothed force
+
+  for (int i = -_range; i <= _range; ++i) {
+    for (int j = -_range; j <= _range; ++j) {
+      for (int k = -_range; k <= _range; ++k) {
+        if (this->_sGeometry.getBlockGeometry(locIC).getMaterial(
+              latticeRoundedPosP[0] + i, latticeRoundedPosP[1] + j,
+              latticeRoundedPosP[2] + k) == material) {
+
+          tempDelta = _delta[i + _range][j + _range][k + _range];
+
+          F[0] = -latticeForceP[0] * tempDelta / (T)(subCycles);
+          F[1] = -latticeForceP[1] * tempDelta / (T)(subCycles);
+          F[2] = -latticeForceP[2] * tempDelta / (T)(subCycles);
+
+          this->_sLattice.getBlockLattice(locIC).get (
+                   latticeRoundedPosP[0] + i,
+                   latticeRoundedPosP[1] + j,
+                   latticeRoundedPosP[2] + k ).template addField<descriptors::FORCE>( F );
+        }
+      }
+    }
+  }
+  return true;
+}
+
+
+////////////////////// Class LocalDeltaBackCouplingModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+LocalBackCouplingModel<T,Lattice,Particle>::LocalBackCouplingModel (
+                 UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry )
+         : BaseBackCouplingModel<T,Lattice,Particle>(converter, sLattice, sGeometry)
+{}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+bool LocalBackCouplingModel<T,Lattice,Particle>::operator() (Particle<T>* p, int globic, int material, int subCycles)
+{
+  int locIC = this->_sLattice.getLoadBalancer().loc(globic);
+
+  // reading the force from the value stored inside the particle
+  std::vector<T> physForceP = p->getStoreForce(); // physical force acting on the particle
+
+  T latticeForceP[3] = {T(), T(), T()}; // dimensionless force acting on the particle
+  latticeForceP[0] = physForceP[0] / this->_converter.getConversionFactorForce();
+  latticeForceP[1] = physForceP[1] / this->_converter.getConversionFactorForce();
+  latticeForceP[2] = physForceP[2] / this->_converter.getConversionFactorForce();
+
+  T physPosP[3] = {T(), T(), T()}; // particle's physical position
+  physPosP[0] = (p->getPos()[0]);
+  physPosP[1] = (p->getPos()[1]);
+  physPosP[2] = (p->getPos()[2]);
+
+  // particle's dimensionless position, rounded at neighbouring voxel
+  int latticeRoundedPosP[3] = {0, 0, 0};
+  this->_sLattice.getCuboidGeometry().get(globic).getLatticeR (
+           latticeRoundedPosP, physPosP );
+
+  if (this->_sGeometry.getBlockGeometry(locIC).getMaterial(
+        latticeRoundedPosP[0], latticeRoundedPosP[1],
+        latticeRoundedPosP[2]) == material) {
+
+    T F[3] = {T(), T(), T()}; // dimensionless smoothed force
+    F[0] = -latticeForceP[0] / (T)(subCycles);
+    F[1] = -latticeForceP[1] / (T)(subCycles);
+    F[2] = -latticeForceP[2] / (T)(subCycles);
+
+    this->_sLattice.getBlockLattice(locIC).get (
+             latticeRoundedPosP[0],
+             latticeRoundedPosP[1],
+             latticeRoundedPosP[2] ).template addField<descriptors::FORCE>( F );
+  }
+
+  return true;
+}
+
+
+////////////////////// Class NonLocalBaseBackCouplingModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+NonLocalBaseBackCouplingModel<T,Lattice,Particle>::NonLocalBaseBackCouplingModel (
+                         UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry,
+                         SmoothingFunctional<T, Lattice>& smoothingFunctional )
+         : BaseBackCouplingModel<T,Lattice,Particle>(converter, sLattice, sGeometry),
+           _smoothingFunctional(smoothingFunctional)
+{}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+bool NonLocalBaseBackCouplingModel<T,Lattice,Particle>::operator() (Particle<T>* p, int globic, int material, int subCycles)
+{
+  int locIC = this->_sLattice.getLoadBalancer().loc(globic);
+
+  // reading the force from the value stored inside the particle
+  std::vector<T> physForceP = p->getStoreForce(); // physical force acting on the particle
+  T latticeForceP[3] = {T(), T(), T()}; // dimensionless force acting on the particle
+  latticeForceP[0] = physForceP[0] / this->_converter.getConversionFactorForce();
+  latticeForceP[1] = physForceP[1] / this->_converter.getConversionFactorForce();
+  latticeForceP[2] = physForceP[2] / this->_converter.getConversionFactorForce();
+
+  // Updating force through voxels within kernel smoothing length from the bubble's position
+  for (int i=0; i<this->_smoothingFunctional.getSize(); i++) {
+
+    // Position of the iterated voxel
+    int iLatticePosF[3] = {0, 0, 0};
+    this->_smoothingFunctional.getLatticePos(iLatticePosF, i);
+
+    // Updating iterated voxel
+    if (this->_sGeometry.getBlockGeometry(locIC).getMaterial(
+          iLatticePosF[0], iLatticePosF[1],
+          iLatticePosF[2]) == material) {
+
+      // Weighted force acting on the iterated voxel
+      T F[3] = {T(), T(), T()}; // dimensionless smoothed force
+      F[0] = -latticeForceP[0] * this->_smoothingFunctional.getWeight(i) / (T)(subCycles);
+      F[1] = -latticeForceP[1] * this->_smoothingFunctional.getWeight(i) / (T)(subCycles);
+      F[2] = -latticeForceP[2] * this->_smoothingFunctional.getWeight(i) / (T)(subCycles);
+
+      this->_sLattice.getBlockLattice(locIC).get (
+              iLatticePosF[0], iLatticePosF[1], iLatticePosF[2] ).template addField<descriptors::FORCE>( F );
+    }
+  }
+  return true;
+}
+
+}
+
+#endif
diff --git a/src/particles/twoWayCouplings/dragModels3D.h b/src/particles/twoWayCouplings/dragModels3D.h
new file mode 100644
index 0000000..0f22429
--- /dev/null
+++ b/src/particles/twoWayCouplings/dragModels3D.h
@@ -0,0 +1,113 @@
+/*  Lattice Boltzmann sample, written in C++, using the OpenLB
+ *  library
+ *
+ *  Copyright (C) 2019 Davide Dapelo
+ *  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.
+ */
+
+/* Drag force models for Lagrangian two-way coupling -- header file.
+ */
+
+#ifndef LB_DRAG_MODELS_H
+#define LB_DRAG_MODELS_H
+
+#include "functors/lattice/reductionF3D.h"
+#include "twoWayHelperFunctionals.h"
+
+namespace olb {
+
+/** Abstact base class for DragModelBase.
+  * Its raison d'etre consists of not being templetized in Lattice.
+  */
+template<typename T, template<typename V> class Particle>
+class DragModel {
+public:
+  /// Returns the scalar drag coefficient to overload. globicFull = { globic, latticeRoundedP[0, ..., 2] }
+  virtual T operator() (Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[])=0;
+protected:
+  /// Functional to compute particle Reynolds number
+  std::shared_ptr<ParticleReynoldsNumber<T, Particle> > _reP;
+};
+
+/** Abstact class for all the drag models.
+  * The virtual method computeDragCoeff returns the drag coefficient.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class DragModelBase : public DragModel<T,Particle> {
+public:
+  /// Constructor
+  DragModelBase(UnitConverter<T, Lattice>& converter);
+  /// Returns the scalar drag coefficient to overload.
+  //virtual T operator() (Particle<T>* p, T latticeVelF[], T latticeVelP[], int globic)=0;
+protected:
+  UnitConverter<T, Lattice>& _converter; // reference to a UnitConverter
+};
+
+/** Class to compute a drag coefficient Cd=1.83 for low-Re Stokes drag.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class StokesSimplifiedDragModel : public DragModelBase<T,Lattice,Particle> {
+public:
+  /// Constructor
+  StokesSimplifiedDragModel(UnitConverter<T, Lattice>& converter);
+  /// Returns the scalar drag coefficient. globicFull = { globic, latticeRoundedP[0, ..., 2] }
+  virtual T operator() (Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[]) override;
+};
+
+/** Class to compute the standard drag coefficient
+  * as in Morsi and Alexander (1972).
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class MorsiDragModel : public DragModelBase<T,Lattice,Particle> {
+public:
+  /// Constructor
+  MorsiDragModel(UnitConverter<T, Lattice>& converter);
+  /// Returns the scalar drag coefficient. globicFull = { globic, latticeRoundedP[0, ..., 2] }
+  virtual T operator() (Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[]) override;
+};
+
+/** Class to compute the drag coefficient for gas bubbles in a liquid fluid phase
+  * as in Dewsbury et al. (1999).
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class DewsburyDragModel : public DragModelBase<T,Lattice,Particle> {
+public:
+  /// Constructor
+  DewsburyDragModel(UnitConverter<T, Lattice>& converter);
+  /// Returns the scalar drag coefficient. globicFull = { globic, latticeRoundedP[0, ..., 2] }
+  virtual T operator() (Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[]) override;
+};
+
+/** Class to compute the drag coefficient for gas bubbles in a liquid fluid phase
+  * as in Dewsbury et al. (1999), in a power-law fluid.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class PowerLawDewsburyDragModel : public DewsburyDragModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  PowerLawDewsburyDragModel ( 
+        UnitConverter<T, Lattice>& converter, SuperLattice3D<T, Lattice>& sLattice );
+};
+
+
+}
+
+#endif
diff --git a/src/particles/twoWayCouplings/dragModels3D.hh b/src/particles/twoWayCouplings/dragModels3D.hh
new file mode 100644
index 0000000..0027544
--- /dev/null
+++ b/src/particles/twoWayCouplings/dragModels3D.hh
@@ -0,0 +1,150 @@
+/*  Lattice Boltzmann sample, written in C++, using the OpenLB
+ *  library
+ *
+ *  Copyright (C) 2019 Davide Dapelo
+ *  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.
+ */
+
+/* Drag force models for Lagrangian two-way coupling -- generic implementation.
+ */
+
+#ifndef LB_DRAG_MODELS_HH
+#define LB_DRAG_MODELS_HH
+
+namespace olb {
+
+
+////////////////////// Class DragModelBase ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+DragModelBase<T,Lattice,Particle>::DragModelBase(UnitConverter<T, Lattice>& converter)
+         : _converter(converter)
+{}
+
+
+////////////////////// Class StokesSimplifiedDragModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+StokesSimplifiedDragModel<T,Lattice,Particle>::StokesSimplifiedDragModel(UnitConverter<T, Lattice>& converter)
+         : DragModelBase<T,Lattice,Particle>(converter)
+{}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+T StokesSimplifiedDragModel<T,Lattice,Particle>::operator() (
+                         Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[] )
+{
+  return 1.83;
+}
+
+
+////////////////////// Class MorsiDragModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+MorsiDragModel<T,Lattice,Particle>::MorsiDragModel(UnitConverter<T, Lattice>& converter)
+         : DragModelBase<T,Lattice,Particle>(converter)
+{
+  this->_reP = std::make_shared<NewtonianParticleReynoldsNumber<T,Lattice,Particle> > (this->_converter);
+}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+T MorsiDragModel<T,Lattice,Particle>::operator() (
+                         Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[] )
+{
+  T physVelRelative = this->_converter.getPhysVelocity (
+                             sqrt( pow(latticeVelF[0] - latticeVelP[0],2) +
+                                   pow(latticeVelF[1] - latticeVelP[1],2) +
+                                   pow(latticeVelF[2] - latticeVelP[2],2) ) );
+
+  T ReP = this->_reP->operator() (p, physVelRelative, globicFull);
+
+  T a[3] = {T(), T(), T()};
+  if (ReP < 0.1) {
+    a[0] = 0.0;     a[1] = 24.0;      a[2] = 0.0;
+  }
+  else if (ReP < 1.0) {
+    a[0] = 3.69;    a[1] = 22.73;     a[2] = 0.0903;
+  }
+  else if (ReP < 10.0) {
+    a[0] = 1.222;   a[1] = 29.16667;  a[2] =-3.8889;
+  }
+  else if (ReP < 100.0) {
+    a[0] = 0.6167;  a[1] = 46.5;      a[2] =-116.67;
+  }
+  else if (ReP < 1000.0) {
+    a[0] = 0.3644;  a[1] = 498.33;    a[2] =-2778;
+  }
+  else if (ReP < 5000.0) {
+    a[0] = 0.357;   a[1] = 148.62;    a[2] =-4.75e4;
+  }
+  else if (ReP < 10000.0) {
+    a[0] = 0.46;    a[1] =-490.546;   a[2] = 57.87e4;
+  }
+  else {
+    a[0] = 0.5191;  a[1] =-1662.5;    a[2] = 5.4167e6;
+  }
+
+
+  return ( a[0] + a[1]/ReP + a[2]/(ReP*ReP) ) * physVelRelative;
+}
+
+
+////////////////////// Class DewsburyDragModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+DewsburyDragModel<T,Lattice,Particle>::DewsburyDragModel(UnitConverter<T, Lattice>& converter)
+         : DragModelBase<T,Lattice,Particle>(converter)
+{
+  this->_reP = std::make_shared<NewtonianParticleReynoldsNumber<T,Lattice,Particle> > (this->_converter);
+}
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+T DewsburyDragModel<T,Lattice,Particle>::operator() (
+                         Particle<T>* p, T latticeVelF[], T latticeVelP[], int globicFull[] )
+{
+  T physVelRelative = this->_converter.getPhysVelocity (
+                             sqrt( pow(latticeVelF[0] - latticeVelP[0],2) +
+                                   pow(latticeVelF[1] - latticeVelP[1],2) +
+                                   pow(latticeVelF[2] - latticeVelP[2],2) ) );
+
+  T ReP = this->_reP->operator() (p, physVelRelative, globicFull);
+
+  T Cd = 0.95;
+  if (ReP <= 195.) {
+    Cd = 16./ReP * (1. + 0.173*pow(ReP, 0.657))
+       + 0.413 / (1. + 16300*pow(ReP, -1.09));
+  }
+  return Cd * this->_converter.getLatticeVelocity(physVelRelative);
+}
+
+
+////////////////////// Class PowerLawDewsburyDragModel ////////////////////////
+
+template<typename T, typename Lattice, template<typename V> class Particle>
+PowerLawDewsburyDragModel<T,Lattice,Particle>::PowerLawDewsburyDragModel (
+        UnitConverter<T, Lattice>& converter, SuperLattice3D<T, Lattice>& sLattice )
+         : DewsburyDragModel<T,Lattice,Particle>(converter)
+{
+  this->_reP = std::make_shared<PowerLawParticleReynoldsNumber<T,Lattice,Particle> > (this->_converter, sLattice);
+}
+
+
+}
+
+#endif
diff --git a/src/particles/twoWayCouplings/forwardCouplingModels3D.h b/src/particles/twoWayCouplings/forwardCouplingModels3D.h
new file mode 100644
index 0000000..17ff63c
--- /dev/null
+++ b/src/particles/twoWayCouplings/forwardCouplingModels3D.h
@@ -0,0 +1,148 @@
+/*  Lattice Boltzmann sample, written in C++, using the OpenLB
+ *  library
+ *
+ *  Copyright (C) 2019 Davide Dapelo
+ *  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.
+ */
+
+/* Models for Lagrangian forward-coupling methods -- header file.
+ */
+
+#ifndef LB_FORWARD_COUPLING_MODELS_H
+#define LB_FORWARD_COUPLING_MODELS_H
+
+#include "functors/lattice/reductionF3D.h"
+#include "twoWayHelperFunctionals.h"
+
+namespace olb {
+
+/** Abstact base class for LocalBaseCouplingModel.
+  * Its raison d'etre consists of not being templetized in Lattice.
+  */
+template<typename T, template<typename V> class Particle>
+class ForwardCouplingModel {
+public:
+  /// Class operator to apply the coupling, for overload.
+  virtual bool operator() (Particle<T>* p, int globic)=0;
+};
+
+/** Abstact class for all the local forward-coupling models,
+  * viz., momentum coupling from fluid to particle.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class LocalBaseForwardCouplingModel : public ForwardCouplingModel<T,Particle> {
+public:
+  /// Class operator to apply the coupling, for overload.
+  virtual bool operator() (Particle<T>* p, int globic) override;
+protected:
+  /// Constructor
+  LocalBaseForwardCouplingModel ( UnitConverter<T, Lattice>& converter,
+                         SuperLattice3D<T, Lattice>& sLattice,
+                         SuperGeometry3D<T>& sGeometry,
+                         DragModel<T, Particle>& dragModel );
+  SuperGeometry3D<T>& _sGeometry;
+  UnitConverter<T, Lattice>& _converter; // reference to a UnitConverter
+  SuperLattice3D<T, Lattice>& _sLattice; // reference to a lattice
+  DragModel<T, Particle>& _dragModel; // reference to a drag model
+  // Functional to interpolate lattice density at particle's location
+  std::shared_ptr<SuperLatticeInterpDensity3Degree3D<T, Lattice> > _interpLatticeDensity;
+  // Functional to interpolate lattice velocity at particle's location
+  std::shared_ptr<SuperLatticeInterpPhysVelocity3D<T, Lattice> > _interpLatticeVelocity;
+  // Momentum-exchange helper functional
+  std::shared_ptr<TwoWayHelperFunctional<T, Lattice> > _momentumExchange;
+};
+
+/** Class for a naive forward-coupling model.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class NaiveForwardCouplingModel : public LocalBaseForwardCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  NaiveForwardCouplingModel ( UnitConverter<T, Lattice>& converter,
+                              SuperLattice3D<T, Lattice>& sLattice,
+                              SuperGeometry3D<T>& sGeometry,
+                              DragModel<T, Particle>& dragModel );
+};
+
+/** Class for a forward-coupling model following the Ladd's mechanism.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class LaddForwardCouplingModel : public LocalBaseForwardCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  LaddForwardCouplingModel ( UnitConverter<T, Lattice>& converter,
+                             SuperLattice3D<T, Lattice>& sLattice,
+                             SuperGeometry3D<T>& sGeometry,
+                             DragModel<T, Particle>& dragModel );
+};
+
+/** Abstact class for all the non-local forward-coupling models,
+  * viz., momentum coupling from fluid to particle.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class NonLocalBaseForwardCouplingModel : public ForwardCouplingModel<T,Particle> {
+public:
+  /// Class operator to apply the coupling, for overload.
+  virtual bool operator() (Particle<T>* p, int globic) override;
+protected:
+  /// Constructor
+  NonLocalBaseForwardCouplingModel ( UnitConverter<T, Lattice>& converter,
+                              SuperLattice3D<T, Lattice>& sLattice,
+                              SuperGeometry3D<T>& sGeometry,
+                              DragModel<T, Particle>& dragModel,
+                              SmoothingFunctional<T, Lattice>& smoothingFunctional );
+  SuperGeometry3D<T>& _sGeometry;
+  UnitConverter<T, Lattice>& _converter; // reference to a UnitConverter
+  SuperLattice3D<T, Lattice>& _sLattice; // reference to a lattice
+  DragModel<T, Particle>& _dragModel; // reference to a drag model
+  SmoothingFunctional<T, Lattice>& _smoothingFunctional; // Functional to treat non-local smoothing
+  // Functional to interpolate lattice density at particle's location.
+  // It is assumed that it returns the exact value for the exact cell's location!
+  std::shared_ptr<SuperLatticeInterpDensity3Degree3D<T, Lattice> > _interpLatticeDensity;
+  // Functional to interpolate lattice velocity at particle's location
+  // It is assumed that it returns the exact value for the exact cell's location!
+  std::shared_ptr<SuperLatticeInterpPhysVelocity3D<T, Lattice> > _interpLatticeVelocity;
+  // Momentum-exchange helper functional
+  std::shared_ptr<TwoWayHelperFunctional<T, Lattice> > _momentumExchange;
+};
+
+/** Class for a naive, non-local forward-coupling model as in Sungkorn et al. (2011), but with
+  * an extra-normalization of the smoothing function.
+  * Input parameters in attice units.
+  */
+template<typename T, typename Lattice, template<typename V> class Particle>
+class NaiveNonLocalForwardCouplingModel : public NonLocalBaseForwardCouplingModel<T,Lattice,Particle> {
+public:
+  /// Constructor
+  NaiveNonLocalForwardCouplingModel ( UnitConverter<T, Lattice>& converter,
+                                 SuperLattice3D<T, Lattice>& sLattice,
+                                 SuperGeometry3D<T>& sGeometry,
+                                 DragModel<T, Particle>& dragModel,
+                                 SmoothingFunctional<T, Lattice>& smoothingFunctional );
+};
+
+
+}
+
+#endif
diff --git a/src/particles/twoWayCouplings/forwardCouplingModels3D.hh b/src/particles/twoWayCouplings/forwardCouplingModels3D.hh
new file mode 100644
index 0000000..b07d50b
--- /dev/null
+++ b/src/particles/twoWayCouplings/forwardCouplingModels3D.hh
@@ -0,0 +1,280 @@
+/*  Lattice Boltzmann sample, written in C++,