SpECTRE  v2024.04.12
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RelativisticEuler::Valencia::FixConservatives< Dim > Class Template Reference

Fix conservative variables using the method proposed in F. Foucart's PhD thesis (Cornell) More...

#include <FixConservatives.hpp>

Classes

struct  CutoffD
 The cutoff below which \(D\) is set to MinimumValueOfD More...
 
struct  MinimumValueOfD
 The minimum value of the rest mass density times the Lorentz factor, \(D\). More...
 
struct  SafetyFactorForS
 The safety factor to fix \(\tilde S_i\). More...
 

Public Types

using options = tmpl::list< MinimumValueOfD, CutoffD, SafetyFactorForS >
 
using return_tags = tmpl::list< RelativisticEuler::Valencia::Tags::TildeD, RelativisticEuler::Valencia::Tags::TildeTau, RelativisticEuler::Valencia::Tags::TildeS< Dim > >
 
using argument_tags = tmpl::list< gr::Tags::InverseSpatialMetric< DataVector, Dim >, gr::Tags::SqrtDetSpatialMetric< DataVector > >
 

Public Member Functions

 FixConservatives (const FixConservatives &)=default
 
FixConservatives & operator= (const FixConservatives &)=default
 
 FixConservatives (FixConservatives &&)=default
 
FixConservatives & operator= (FixConservatives &&)=default
 
 FixConservatives (double minimum_rest_mass_density_times_lorentz_factor, double rest_mass_density_times_lorentz_factor_cutoff, double safety_factor_for_momentum_density, const Options::Context &context={})
 
void pup (PUP::er &p)
 
void operator() (gsl::not_null< Scalar< DataVector > * > tilde_d, gsl::not_null< Scalar< DataVector > * > tilde_tau, gsl::not_null< tnsr::i< DataVector, Dim, Frame::Inertial > * > tilde_s, const tnsr::II< DataVector, Dim, Frame::Inertial > &inv_spatial_metric, const Scalar< DataVector > &sqrt_det_spatial_metric) const
 

Static Public Attributes

static constexpr Options::String help
 

Friends

template<size_t SpatialDim>
bool operator== (const FixConservatives< SpatialDim > &lhs, const FixConservatives< SpatialDim > &rhs)
 

Detailed Description

template<size_t Dim>
class RelativisticEuler::Valencia::FixConservatives< Dim >

Fix conservative variables using the method proposed in F. Foucart's PhD thesis (Cornell)

Fix the conservative variables at each grid point according to the following recipe:

  • If \(D < D_\text{cutoff}\), set \(D = D_\text{min}\)
  • If \(\tau < 0\), set \(\tau = 0\)

  • If \(\tilde S^2 > \tilde S_\text{max}^2 = \tilde\tau(\tilde\tau + 2\tilde D)\), rescale \(\tilde S_i\) by the factor

    \begin{align*} f = \sqrt{\frac{(1 - \epsilon)\tilde S_\text{max}^2}{\tilde S^2 + 10^{-16}\tilde D^2}} < 1 \end{align*}

(if \( f\geq 1\), do not fix \(\tilde S_i\)), where \(D_\text{min}\), \(D_\text{cutoff}\) and \(\epsilon\) are small and positive input parameters, typically chosen in consistency with some variable fixing applied to the primitives variables (e.g. VariableFixing::FixToAtmosphere). Note that, in order to fix \(\tilde S_i\), \(\epsilon\) is chosen so that \(1 - \epsilon\) (the relevant quantity used in the equations) is sufficiently close (but smaller) than 1.

Member Data Documentation

◆ help

template<size_t Dim>
constexpr Options::String RelativisticEuler::Valencia::FixConservatives< Dim >::help
staticconstexpr
Initial value:
= {
"Variable fixing used in Foucart's thesis."}
The documentation for this class was generated from the following file: