# file

MixMassFractionBetaCoeffPolicy.hppMix mass-fraction beta SDE coefficients policies.

### Contents

- Reference

This file declares coefficients policy classes for the mix mass-fraction beta SDE, defined in DiffEq/Beta/MixMassFractionBeta.h.

General requirements on mix mass-fraction beta SDE coefficients policy classes:

- Must define a
*constructor*, which is used to initialize the SDE coefficients, b, S, kappa, rho2, and r. Required signature:CoeffPolicyName( tk::ctr::ncomp_t ncomp, const std::vector< kw::sde_bprime::info::expect::type >& bprime_, const std::vector< kw::sde_S::info::expect::type >& S_, const std::vector< kw::sde_kappaprime::info::expect::type >& kprime_, const std::vector< kw::sde_rho2::info::expect::type >& rho2_, const std::vector< kw::sde_r::info::expect::type >& r_, std::vector< kw::sde_bprime::info::expect::type >& bprime, std::vector< kw::sde_S::info::expect::type >& S, std::vector< kw::sde_kappaprime::info::expect::type >& kprime, std::vector< kw::sde_rho2::info::expect::type >& rho2_, std::vector< kw::sde_r::info::expect::type >& r_ );

where

- ncomp denotes the number of scalar components of the system of mix mass-fraction beta SDEs.
- Constant references to bprime_, S_, kprime_, rho2_, and r_, which denote vectors of real values used to initialize the parameter vectors of the system of mix mass-fraction beta SDEs. The length of the vectors must be equal to the number of components given by ncomp.
- References to bprime, S, kprime, rho2_, and r, which denote the parameter vectors to be initialized based on bprime_, S_, kprime_, rho2_, and r_.

Must define the static function

*type()*, returning the enum value of the policy option. Example:static ctr::CoeffPolicyType type() noexcept { return ctr::CoeffPolicyType::DECAY; }

which returns the enum value of the option from the underlying option class, collecting all possible options for coefficients policies.

Must define the function

*update()*, called from MixMassFractionBeta::advance(), updating the model coefficients. Required signature:void update( char depvar, char dissipation_depvar, char velocity_depvar, ctr::DepvarType velocity_solve, ctr::DepvarType solve, ncomp_t ncomp, const std::map< tk::ctr::Product, tk::real >& moments, const std::vector< kw::sde_bprime::info::expect::type >& bprime, const std::vector< kw::sde_kappaprime::info::expect::type >& kprime, const std::vector< kw::sde_rho2::info::expect::type >& rho2, const std::vector< kw::sde_r::info::expect::type >& r, const std::vector< tk::Table<1> >& hts, const std::vector< tk::Table<1> >& hp, std::vector< kw::sde_b::info::expect::type >& b, std::vector< kw::sde_kappa::info::expect::type >& k, std::vector< kw::sde_S::info::expect::type >& S ) const {}

where

*depvar*is the dependent variable associated with the mix mass-fraction beta SDE, specified in the control file by the user,*dissipation_depvar*is a character labeling the coupled dissipation equation,*velocity_depvar*is an is a character labeling the coupled velocity equation,*velocity_solve*is an enum selecting whether the coupled velocity equation solves for full variable or its fluctuation,*solve*is an enum selecting whether the mixmassfracbeta (scalar) equation solves for full variable or its fluctuation,*ncomp*is the number of components in the system,*moments*is the map associating moment IDs (tk::ctr::vector< tk::ctr::Term >) to values of statistical moments,*bprime*,*kprime*, rho2, r, are user-defined parameters, and*b*,*k*,*S*, are the SDE parameters computed, see DiffEq/Beta/MixMassFractionBeta.h.The constant reference to hts, denotes a vector of y=f(x) functions (see src/DiffEq/Beta/HydroTimeScales.h and src/Control/Walker/Options/HydroTimescales.h) used to configure the inverse hydrodynamics time scales (extracted from direct numerical simulations) of the system of mix mass-fraction beta SDEs if the MixMassFracBetaCoeffHydroTimeScaleHomDecay coefficients policy is selected. The length of this vector must be equal to the number of components given by ncomp. Note that hts is only used by MixMassFracBetaCoeffHydroTimeScaleHomDecay.

The constant reference to hp, denotes a vector of y=f(x) functions (see src/DiffEq/Beta/HydroProductions.h and src/Control/Walker/Options/HydroProductions.h) used to configure the turbulent kinetic energy production divided by the dissipation rate, P/e, a measure of the non-eqilibrium nature of the turbulent flow (extracted from direct numerical simulations) of the system of mix mass-fraction beta SDEs if the MixMassFracBetaCoeffHydroTimeScaleHomDecay coefficients policy is selected. The length of this vector must be equal to the number of components given by ncomp. Note that hp is only used by MixMassFracBetaCoeffHydroTimeScaleHomDecay.

## Namespaces

- namespace walker
- Walker declarations and definitions.

## Classes

- class walker::MixMassFracBetaCoeffDecay
- Mix mass-fraction beta SDE decay coefficients policy.
- class walker::MixMassFracBetaCoeffHomDecay
- Mix mass-fraction beta SDE homogneous decay coefficients policy.
- class walker::MixMassFracBetaCoeffMonteCarloHomDecay
- Mix mass-fraction beta SDE Monte Carlo homogenous decay coefficients policy.
- class walker::MixMassFracBetaCoeffHydroTimeScale
- Mix mass-fraction beta SDE coefficients policy with DNS hydrodynamics time scale.
- class walker::MixMassFracBetaCoeffInstVel
- Mix mass-fraction beta SDE coefficients policy coupled to velocity.