Implementation of the dual BGK collision step with external force. More...

#include <dualDynamics.h>

Inheritance diagram for olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >:

Collaboration diagram for olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >:

Public Types
using	MomentaF = typename MOMENTA::template type<DESCRIPTOR>

Public Types inherited from olb::dynamics::CustomCollision< T, DESCRIPTOR, MOMENTA >
using	value_t = T

using	descriptor_t = DESCRIPTOR

using	MomentaF = typename MOMENTA::template type<DESCRIPTOR>

Public Types inherited from olb::Dynamics< T, DESCRIPTOR >
using	value_t = T

using	descriptor_t = DESCRIPTOR

Public Member Functions
	DualPorousBGKdynamics (T omega_)
	Constructor.

virtual T	computeEquilibrium (int iPop, T rho, const T u[DESCRIPTOR::d]) const
	Compute equilibrium distribution function.

virtual void	computeRhoU (const T fPop[DESCRIPTOR::q], T &rho, T u[DESCRIPTOR::d]) const
	Compute moments.

virtual CellStatistic< T >	collide (Cell< T, DESCRIPTOR > &cell)
	Collision step.

virtual T	getOmega () const
	Get local relaxation parameter of the dynamics.

virtual void	setOmega (T omega_)
	Set local relaxation parameter of the dynamics.

virtual void	defineRho (Cell< T, DESCRIPTOR > &cell, T rho)
	Does nothing.

Public Member Functions inherited from olb::legacy::BasicDynamics< T, DESCRIPTOR, MOMENTA >
std::type_index	id () override
	Expose unique type-identifier for RTTI.

AbstractParameters< T, DESCRIPTOR > &	getParameters (BlockLattice< T, DESCRIPTOR > &block) override
	Parameters access for legacy post processors.

Public Member Functions inherited from olb::dynamics::CustomCollision< T, DESCRIPTOR, MOMENTA >
void	initialize (Cell< T, DESCRIPTOR > &cell) override
	Initialize dynamics-specific data for cell.

T	computeRho (ConstCell< T, DESCRIPTOR > &cell) const override
	Compute particle density.

void	computeU (ConstCell< T, DESCRIPTOR > &cell, T u[DESCRIPTOR::d]) const override
	Compute fluid velocity.

void	computeJ (ConstCell< T, DESCRIPTOR > &cell, T j[DESCRIPTOR::d]) const override
	Compute fluid momentum.

void	computeStress (ConstCell< T, DESCRIPTOR > &cell, T rho, const T u[DESCRIPTOR::d], T pi[util::TensorVal< DESCRIPTOR >::n]) const override
	Compute stress tensor.

void	computeRhoU (ConstCell< T, DESCRIPTOR > &cell, T &rho, T u[DESCRIPTOR::d]) const override
	Compute fluid velocity and particle density.

void	computeAllMomenta (ConstCell< T, DESCRIPTOR > &cell, T &rho, T u[DESCRIPTOR::d], T pi[util::TensorVal< DESCRIPTOR >::n]) const override
	Compute all momenta up to second order.

void	defineU (Cell< T, DESCRIPTOR > &cell, const T u[DESCRIPTOR::d]) override
	Set fluid velocity.

void	defineRhoU (Cell< T, DESCRIPTOR > &cell, T rho, const T u[DESCRIPTOR::d]) override
	Define fluid velocity and particle density.

void	defineAllMomenta (Cell< T, DESCRIPTOR > &cell, T rho, const T u[DESCRIPTOR::d], const T pi[util::TensorVal< DESCRIPTOR >::n]) override
	Define all momenta up to second order.

void	inverseShiftRhoU (ConstCell< T, DESCRIPTOR > &cell, T &rho, T u[DESCRIPTOR::d]) const override
	Calculate population momenta s.t. the physical momenta are reproduced by the computeRhoU.

Public Member Functions inherited from olb::Dynamics< T, DESCRIPTOR >
virtual	~Dynamics () any_platform

virtual std::string	getName () const
	Return human-readable name.

void	iniEquilibrium (Cell< T, DESCRIPTOR > &cell, T rho, const T u[DESCRIPTOR::d])
	Initialize to equilibrium distribution.

void	iniRegularized (Cell< T, DESCRIPTOR > &cell, T rho, const T u[DESCRIPTOR::d], const T pi[util::TensorVal< DESCRIPTOR >::n])
	Initialize cell to equilibrium and non-equilibrum part.

Detailed Description

template<typename T, typename DESCRIPTOR, typename MOMENTA = momenta::BulkTuple>
class olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >

Implementation of the dual BGK collision step with external force.

Definition at line 273 of file dualDynamics.h.

Member Typedef Documentation

◆ MomentaF

template<typename T , typename DESCRIPTOR , typename MOMENTA = momenta::BulkTuple>

using olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::MomentaF = typename MOMENTA::template type<DESCRIPTOR>

Definition at line 275 of file dualDynamics.h.

Constructor & Destructor Documentation

◆ DualPorousBGKdynamics()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::DualPorousBGKdynamics ( T omega_ )

Constructor.

Parameters

omega_	relaxation parameter, related to the dynamic viscosity
momenta_	a Momenta object to know how to compute velocity momenta

Definition at line 301 of file dualDynamics.h.

  : legacy::BasicDynamics<T,DESCRIPTOR,MOMENTA>(),
    omega(omega_)
{
  this->getName() = "DualPorousBGKdynamics";
  OLB_PRECONDITION( DESCRIPTOR::template provides<descriptors::POROSITY>() );
}

References olb::Dynamics< T, DESCRIPTOR >::getName(), and OLB_PRECONDITION.

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Member Function Documentation

◆ collide()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

CellStatistic< T > olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::collide ( Cell< T, DESCRIPTOR > & cell )

virtual

Collision step.

Reimplemented from olb::Dynamics< T, DESCRIPTOR >.

Definition at line 348 of file dualDynamics.h.

{
  // Revert for backwards-in-time propagation
  cell.revert();
 
  // Preparation
  auto pop_f =   cell.template getField<descriptors::F>();
  auto dJdF  =   cell.template getFieldPointer<descriptors::DJDF>();
  T d      =  cell.template getField<descriptors::POROSITY>();
 
  // Forward density and velocity
  T rho_f, u_f[DESCRIPTOR::d];
  this->computeRhoU( pop_f.data(), rho_f, u_f);
 
  // Adjoint equilibrium
  T pheq[DESCRIPTOR::q];
  for (int i=0; i < DESCRIPTOR::q; ++i) {
    pheq[i] = T{0};
    for (int j=0; j < DESCRIPTOR::q; ++j) {
      T feq_j = computeEquilibrium(j, rho_f, u_f)
                + descriptors::t<T,DESCRIPTOR>(j);
      T dot_ij = T();
      for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
        dot_ij += ( descriptors::c<DESCRIPTOR>(j,iD) - d*u_f[iD] )
                  * ( descriptors::c<DESCRIPTOR>(i,iD) - u_f[iD] );
      }
      pheq[i] += cell[j]*feq_j*( T{1} + descriptors::invCs2<T,DESCRIPTOR>()*d*dot_ij );
    }
    pheq[i] /= rho_f;
  }
 
  // Collision
  for (int i=0; i < DESCRIPTOR::q; ++i) {
    cell[i] = cell[i] - omega*( cell[i] - pheq[i] ) + dJdF[i];
  }
 
  // Statistics
  T rho_phi, u_phi[DESCRIPTOR::d];
  MomentaF().computeRhoU( cell, rho_phi, u_phi );
  T uSqr_phi = util::normSqr<T,DESCRIPTOR::d>( u_phi );
 
  // Undo revert
  cell.revert();
  return {rho_phi, uSqr_phi};
}

References olb::dynamics::Tuple< T, DESCRIPTOR, MOMENTA, EQUILIBRIUM, COLLISION, COMBINATION_RULE >::computeRhoU(), and olb::Cell< T, DESCRIPTOR >::revert().

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◆ computeEquilibrium()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

T olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::computeEquilibrium	(	int	iPop,
		T	rho,
		const T	u[DESCRIPTOR::d] ) const

virtual

Compute equilibrium distribution function.

Reimplemented from olb::legacy::BasicDynamics< T, DESCRIPTOR, MOMENTA >.

Definition at line 318 of file dualDynamics.h.

{
  // Compute equilibrium minus weights
  // used in iniEquilibrium
  return equilibrium<DESCRIPTOR>::secondOrder(iPop, rho, u);
}

References olb::equilibrium< DESCRIPTOR >::secondOrder().

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◆ computeRhoU()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

void olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::computeRhoU	(	const T	fPop[DESCRIPTOR::q],
		T &	rho,
		T	u[DESCRIPTOR::d] ) const

virtual

Compute moments.

Definition at line 328 of file dualDynamics.h.

{
  rho_f = T();
  for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
    u_f[iD] = T();
  }
  for (int iPop=0; iPop < DESCRIPTOR::q; ++iPop) {
    rho_f += fPop[iPop];
    for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
      u_f[iD] += fPop[iPop]*descriptors::c<DESCRIPTOR>(iPop,iD);
    }
  }
  rho_f += (T)1;
  for (int iD=0; iD < DESCRIPTOR::d; ++iD) {
    u_f[iD] /= rho_f;
  }
}

◆ defineRho()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

void olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::defineRho	(	Cell< T, DESCRIPTOR > &	cell,
		T	rho )

virtual

Does nothing.

Reimplemented from olb::dynamics::CustomCollision< T, DESCRIPTOR, MOMENTA >.

Definition at line 311 of file dualDynamics.h.

{
  // The meaning of this function is not clear. Please contact Julius.
  throw std::bad_function_call();
}

◆ getOmega()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

T olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::getOmega ( ) const

virtual

Get local relaxation parameter of the dynamics.

Definition at line 396 of file dualDynamics.h.

{
  return omega;
}

◆ setOmega()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

void olb::opti::DualPorousBGKdynamics< T, DESCRIPTOR, MOMENTA >::setOmega ( T omega_ )

virtual

Set local relaxation parameter of the dynamics.

Definition at line 402 of file dualDynamics.h.

{
  omega = omega_;
}

The documentation for this class was generated from the following file:

src/optimization/dualDynamics.h

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

◆ MomentaF

Constructor & Destructor Documentation

◆ DualPorousBGKdynamics()

Member Function Documentation

◆ collide()

◆ computeEquilibrium()

◆ computeRhoU()

◆ defineRho()

◆ getOmega()

◆ setOmega()