hydro::Tags::MassFlux< DataType, Dim, Fr > Struct Template Reference

The vector $J^i$ in $\dot{M}=-\int J^i{s}_i{d}^{2}S$, representing the mass flux through a surface with normal $s_i$. More...

#include <Tags.hpp>

Public Types
using	type = tnsr::I< DataType, Dim, Fr >

Static Public Member Functions
static std::string	name ()

Detailed Description

template<typename DataType, size_t Dim, typename Fr>
struct hydro::Tags::MassFlux< DataType, Dim, Fr >

The vector $J^i$ in $\dot{M}=-\int J^i{s}_i{d}^{2}S$, representing the mass flux through a surface with normal $s_i$.

Note that the integral is understood as a flat-space integral: all metric factors are included in $J^i$. In particular, if the integral is done over a Strahlkorper, the gr::surfaces::euclidean_area_element of the Strahlkorper should be used, and $s_i$ is the normal one-form to the Strahlkorper normalized with the flat metric, $s_i{s}_j{\delta }^{ij}=1$.

The formula is $J^i=\rho W\sqrt{\gamma }(\alpha v^i-{\beta }^i)$, where $\rho$ is the mass density, $W$ is the Lorentz factor, $v^i$ is the spatial velocity of the fluid, $\gamma$ is the determinant of the 3-metric ${\gamma }_{ij}$, $\alpha$ is the lapse, and ${\beta }^i$ is the shift.

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

• src/PointwiseFunctions/Hydro/Tags.hpp