ERF_DiffStruct.H

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#ifndef ERF_DIFF_STRUCT_H_
#define ERF_DIFF_STRUCT_H_
 
#include <string>
#include <iostream>
 
#include <AMReX_ParmParse.H>
#include <AMReX_Print.H>
#include <AMReX_Gpu.H>
 
enum struct MolecDiffType {
    None, Constant, ConstantAlpha
};
 
/**
 * Container holding diffusion-related choices
 */
 
struct DiffChoice {
  public:
    void init_params(std::string pp_prefix)
    {
        amrex::ParmParse pp(pp_prefix);
 
        static std::string molec_diff_type_string = "None";
        pp.query("molec_diff_type",molec_diff_type_string);
 
        if (!molec_diff_type_string.compare("Constant")) {
            molec_diff_type = MolecDiffType::Constant;
        } else if (!molec_diff_type_string.compare("ConstantAlpha")) {
            molec_diff_type = MolecDiffType::ConstantAlpha;
        } else if (!molec_diff_type_string.compare("None")) {
            molec_diff_type = MolecDiffType::None;
        } else {
            amrex::Error("Don't know this molec_diff_type");
        }
 
        if (molec_diff_type != MolecDiffType::None) {
            pp.query("alpha_T", alpha_T);
            pp.query("alpha_C", alpha_C);
            pp.query("dynamic_viscosity", dynamic_viscosity);
            pp.query("rho0_trans", rho0_trans);
        }
 
        // Compute relevant forms of diffusion parameters
        rhoAlpha_T = rho0_trans * alpha_T;
        rhoAlpha_C = rho0_trans * alpha_C;
 
        if (molec_diff_type == MolecDiffType::ConstantAlpha) {
            amrex::Print() << "Using constant kinematic diffusion coefficients" << std::endl;
            amrex::Print() << "  momentum : " << dynamic_viscosity/rho0_trans << " m^2/s" << std::endl;
            amrex::Print() << "  temperature : " << alpha_T << " m^2/s" << std::endl;
            amrex::Print() << "  scalar : " << alpha_C << " m^2/s" << std::endl;
        }
        else if (molec_diff_type == MolecDiffType::Constant) {
            amrex::Print() << "Using constant dynamic diffusion coefficients" << std::endl;
            amrex::Print() << "  momentum : " << dynamic_viscosity << " kg/(m-s)" << std::endl;
            amrex::Print() << "  temperature : " << rhoAlpha_T << " kg/(m-s)" << std::endl;
            amrex::Print() << "  scalar : " << rhoAlpha_C << " kg/(m-s)" << std::endl;
        }
 
    }
 
    void display()
    {
        amrex::Print() << "Diffusion choices: " << std::endl;
        amrex::Print() << "    rho0_trans              : " << rho0_trans << std::endl;
        amrex::Print() << "    alpha_T                 : " << alpha_T << std::endl;
        amrex::Print() << "    alpha_C                 : " << alpha_C << std::endl;
        amrex::Print() << "    dynamic_viscosity       : " << dynamic_viscosity << std::endl;
 
        if (molec_diff_type == MolecDiffType::Constant) {
            amrex::Print() << "Using constant molecular diffusivity (relevant for DNS)" << std::endl;
        } else if (molec_diff_type == MolecDiffType::None) {
            amrex::Print() << "Not using any molecular diffusivity, i.e. using the modeled turbulent diffusivity"
            << std::endl;
        }
    }
 
    // Molecular transport model
    MolecDiffType molec_diff_type = MolecDiffType::Constant;
 
    // Diffusive/viscous coefficients [m2/s]
    amrex::Real alpha_T = 0.0;
    amrex::Real alpha_C = 0.0;
 
    // Density for computation of rhoAlpha (which is assumed constant) [kg/m3]
    amrex::Real rho0_trans = 1.0;
 
    // Dynamic diffusion coefficients [kg/(m-s)]
    amrex::Real rhoAlpha_T = 0.0;
    amrex::Real rhoAlpha_C = 0.0;
    amrex::Real dynamic_viscosity = 0.0;
};
#endif