Implementation of the MRT collision step with stochastic relaxation based on " A stochastic subgrid model with application to turbulent flow and scalar mixing"; Phys. More...

#include <stochasticSGSdynamics.h>

Inheritance diagram for olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >:

Collaboration diagram for olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >:

Public Types
template<typename M >
using	exchange_momenta = StochasticSGSdynamics<T,DESCRIPTOR,M>

Public Types inherited from olb::dynamics::Tuple< T, DESCRIPTOR, MOMENTA, EQUILIBRIUM, COLLISION, COMBINATION_RULE >
using	MomentaF = typename COMBINATION_RULE::template combined_momenta<DESCRIPTOR,MOMENTA>

using	EquilibriumF = typename COMBINATION_RULE::template combined_equilibrium<DESCRIPTOR,MOMENTA,EQUILIBRIUM>

using	CollisionO = typename COMBINATION_RULE::template combined_collision<DESCRIPTOR,MOMENTA,EQUILIBRIUM,COLLISION>

using	parameters = typename COMBINATION_RULE::template combined_parameters<DESCRIPTOR,MOMENTA,EQUILIBRIUM,COLLISION>

template<typename NEW_MOMENTA >
using	exchange_momenta

template<typename NEW_RULE >
using	exchange_combination_rule

template<template< typename > typename WRAPPER>
using	wrap_collision

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

using	descriptor_t = DESCRIPTOR

Public Member Functions
	StochasticSGSdynamics (T omega_, T turbulenceInt_, T charU_, T smagoConst_, T dx_=1, T dt_=1)
	Constructor.

virtual CellStatistic< T >	collide (Cell< T, DESCRIPTOR > &cell, LatticeStatistics< T > &statistics_)

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

virtual T	getSmagorinskyOmega (Cell< T, DESCRIPTOR > &cell_, T X_lang_n_)
	Get local smagorinsky relaxation parameter of the dynamics.

virtual T	getRandBMTrans (Cell< T, DESCRIPTOR > &cell_, T turbulenceInt_, T charU_)
	Get local Random number of BoxMüllertransform -> returns randBM.

virtual T	getRandomWalk (Cell< T, DESCRIPTOR > &cell_, T drift_, T result_)
	Get local Random number of BoxMüllertransform -> returns randBM.

Public Member Functions inherited from olb::dynamics::Tuple< T, DESCRIPTOR, MOMENTA, EQUILIBRIUM, COLLISION, COMBINATION_RULE >
std::type_index	id () override
	Expose unique type-identifier for RTTI.

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

template<typename FIELD >
constexpr bool	hasParameter () const
	Return true iff FIELD is a parameter.

AbstractParameters< T, DESCRIPTOR > &	getParameters (BlockLattice< T, DESCRIPTOR > &block) override
	Interim workaround for accessing dynamics parameters in legacy post processors.

void	initialize (Cell< T, DESCRIPTOR > &cell) override
	Initialize MOMENTA-specific data for cell.

template<CONCEPT(MinimalCell) CELL, typename PARAMETERS , typename V = typename CELL::value_t>
CellStatistic< V >	apply (CELL &cell, PARAMETERS &parameters) any_platform
	Apply purely-local collision step to a generic CELL.

T	computeEquilibrium (int iPop, T rho, const T u[DESCRIPTOR::d]) const override any_platform
	Return iPop equilibrium for given first and second momenta.

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	defineRho (Cell< T, DESCRIPTOR > &cell, T rho) override
	Set particle density.

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 CellStatistic< T >	collide (Cell< T, DESCRIPTOR > &cell)
	Perform purely-local collision step on Cell interface (legacy, to be deprecated)

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.

Additional Inherited Members
Static Public Attributes inherited from olb::dynamics::Tuple< T, DESCRIPTOR, MOMENTA, EQUILIBRIUM, COLLISION, COMBINATION_RULE >
static constexpr bool	is_vectorizable = is_vectorizable_v<CollisionO>

Detailed Description

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

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

Definition at line 39 of file stochasticSGSdynamics.h.

Member Typedef Documentation

◆ exchange_momenta

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

template<typename M >

using olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::exchange_momenta = StochasticSGSdynamics<T,DESCRIPTOR,M>

Definition at line 42 of file stochasticSGSdynamics.h.

Constructor & Destructor Documentation

◆ StochasticSGSdynamics()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::StochasticSGSdynamics	(	T	omega_,
		T	turbulenceInt_,
		T	charU_,
		T	smagoConst_,
		T	dx_ = 1,
		T	dt_ = 1 )

Constructor.

Implementation of the Stochastic relaxation based on " A stochastic subgrid model with application to turbulent flow and scalar mixing"; Phys.

of Fluids 19; 2007

Parameters

vs2_	speed of sound
momenta_	a Momenta object to know how to compute velocity momenta
momenta_	a Momenta object to know how to compute velocity momenta

Definition at line 60 of file stochasticSGSdynamics.hh.

  : MRTdynamics<T,DESCRIPTOR,MOMENTA>(omega_),
    turbulenceInt(turbulenceInt_),
    smagoConst(smagoConst_),
    charU(charU_),
    preFactor(computePreFactor(omega_,smagoConst_) )
 
{
 
  //    T invM_S_SGS[DESCRIPTOR::q][DESCRIPTOR::q];
  //    T rtSGS[DESCRIPTOR::q]; // relaxation times vector for SGS approach.
  //    for (int iPop  = 0; iPop < DESCRIPTOR::q; ++iPop)
  //    {
  //      rtSGS[iPop] = DESCRIPTOR::S[iPop];
  //    }
  //    for (int iPop  = 0; iPop < DESCRIPTOR::shearIndexes; ++iPop)
  //    {
  //      rtSGS[DESCRIPTOR::shearViscIndexes[iPop]] = omega;
  //    }
  //    for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop)
  //    {
  //      for (int jPop = 0; jPop < DESCRIPTOR::q; ++jPop)
  //      {
  //        invM_S_SGS[iPop][jPop] = T();
  //        for (int kPop = 0; kPop < DESCRIPTOR::q; ++kPop)
  //        {
  //          if (kPop == jPop)
  //          {
  //            invM_S_SGS[iPop][jPop] += DESCRIPTOR::invM[iPop][kPop] *
  //                                  rtSGS[kPop];
  //            cout << "wert"<<iPop <<jPop << "= "<<  invM_S_SGS[iPop][jPop]<< std::endl;
  //          }
  //        }
  //      }
  //    }
  //
 
 
}

Member Function Documentation

◆ collide()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

CellStatistic< T > olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::collide	(	Cell< T, DESCRIPTOR > &	cell,
		LatticeStatistics< T > &	statistics_ )

virtual

Definition at line 103 of file stochasticSGSdynamics.hh.

{
  T rho, u[DESCRIPTOR::d], pi[util::TensorVal<DESCRIPTOR >::n];
 
 
 
  T drift  = computeTimeScale(preFactor, rho, pi, smagoConst, X_lang_n);
  T result = getRandBMTrans(cell, turbulenceInt, charU);
 
  //  cout << "vor neu setzen: "<<X_lang_n<< std::endl;
  X_lang_n = getRandomWalk(cell, drift, result);
  // cout << "nach neu setzen: "<<X_lang_n<< std::endl;
  //cout << X_lang_n<< std::endl;
  // cout << drift<< std::endl;
  // cout << result<< std::endl;
 
 
  MOMENTA().computeAllMomenta(cell, rho, u, pi);
  T newOmega = computeOmega(this->getOmega(), preFactor, rho, pi, X_lang_n);
 
 
  T invM_S_SGS[DESCRIPTOR::q][DESCRIPTOR::q];
  T rtSGS[DESCRIPTOR::q]; // relaxation times vector for SGS approach.
  for (int iPop  = 0; iPop < DESCRIPTOR::q; ++iPop) {
    rtSGS[iPop] = DESCRIPTOR::S[iPop];
  }
  for (int iPop  = 0; iPop < DESCRIPTOR::shearIndexes; ++iPop) {
    rtSGS[DESCRIPTOR::shearViscIndexes[iPop]] = newOmega;
  }
  for (int iPop = 0; iPop < DESCRIPTOR::q; ++iPop) {
    for (int jPop = 0; jPop < DESCRIPTOR::q; ++jPop) {
      invM_S_SGS[iPop][jPop] = T();
      for (int kPop = 0; kPop < DESCRIPTOR::q; ++kPop) {
        if (kPop == jPop) {
          invM_S_SGS[iPop][jPop] += DESCRIPTOR::invM[iPop][kPop] *
                                    rtSGS[kPop];
          //cout << "wert"<<iPop <<jPop << "= "<<  invM_S_SGS[iPop][jPop]<< std::endl;
        }
      }
    }
  }
 
  T uSqr = mrt<DESCRIPTOR>::mrtSGSCollision(cell, rho, u, newOmega, invM_S_SGS);
  statistics.incrementStats(rho, uSqr);
}

References olb::LatticeStatistics< T >::incrementStats(), and olb::mrt< DESCRIPTOR >::mrtSGSCollision().

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◆ getRandBMTrans()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

T olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::getRandBMTrans	(	Cell< T, DESCRIPTOR > &	cell_,
		T	turbulenceInt_,
		T	charU_ )

virtual

Get local Random number of BoxMüllertransform -> returns randBM.

Random number generator based on Box Müller transform to produuce random normal distributed numbers with zero mean and

Definition at line 170 of file stochasticSGSdynamics.hh.

{
 
  T mean = 0.;
  T TKE_ini = 1.5*turbulenceInt*turbulenceInt*charU*charU;
  T velStDev =  util::sqrt(2./3.*TKE_ini);
  static double n2 = 0.0;
  static int n2_cached = 0;
  if (!n2_cached) {
    double x, y, r;
    do {
      x = 2.0*rand()/RAND_MAX - 1;
      y = 2.0*rand()/RAND_MAX - 1;
 
      r = x*x + y*y;
    }
    while ( util::nearZero(r) || r > 1.0);
    {
      double d = util::sqrt(-2.0*util::log(r)/r);
      double n1 = x*d;
      n2 = y*d;
      double result = n1*velStDev + mean;
      n2_cached = 1;
      return result;
    }
  }
  else {
    n2_cached = 0;
    return n2*velStDev + mean;
  }
}

References olb::util::log(), olb::util::nearZero(), and olb::util::sqrt().

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◆ getRandomWalk()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

T olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::getRandomWalk	(	Cell< T, DESCRIPTOR > &	cell_,
		T	drift_,
		T	result_ )

virtual

Get local Random number of BoxMüllertransform -> returns randBM.

Create Random walk.

initialisation of model standard variation, see Pope pp 484

Definition at line 209 of file stochasticSGSdynamics.hh.

{
  T sigma = 2.3;
  X_lang_n *=drift;
 
  X_lang_n +=  sigma*util::sqrt(drift*2)*result;
 
  return X_lang_n;
 
 
}

References olb::util::sqrt().

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◆ getSmagorinskyOmega()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

T olb::StochasticSGSdynamics< T, DESCRIPTOR, MOMENTA >::getSmagorinskyOmega	(	Cell< T, DESCRIPTOR > &	cell_,
		T	X_lang_n_ )

virtual

Get local smagorinsky relaxation parameter of the dynamics.

Definition at line 159 of file stochasticSGSdynamics.hh.

{
  T rho, uTemp[DESCRIPTOR::d], pi[util::TensorVal<DESCRIPTOR >::n];
  MOMENTA().computeAllMomenta(cell, rho, uTemp, pi);
  T newOmega = computeOmega(this->getOmega(), preFactor, rho, pi, X_lang_n);
  return newOmega;
}

◆ setOmega()

template<typename T , typename DESCRIPTOR , typename MOMENTA >

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

virtual

Set local relaxation parameter of the dynamics.

Definition at line 152 of file stochasticSGSdynamics.hh.

{
  this->setOmega(omega);
  preFactor = computePreFactor(omega, smagoConst);
}

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

src/dynamics/stochasticSGSdynamics.h
src/dynamics/stochasticSGSdynamics.hh

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ exchange_momenta

Constructor & Destructor Documentation

◆ StochasticSGSdynamics()

Member Function Documentation

◆ collide()

◆ getRandBMTrans()

◆ getRandomWalk()

◆ getSmagorinskyOmega()

◆ setOmega()