2 Basic Equations

The 3D hydrodynamics equations, including source terms due to gravity, are the mass conservation equation

$$\frac{\partial \rho}{\partial t} + \frac{\partial \; \rho \... ...frac{\partial \; \rho \; v{\rm 2}}{\partial x3} = 0 \enspace ,$$ (1)

the momentum equation

$$\frac{\partial }{\partial t} \left( \! \begin{array}{c} ... ...\rho \; g{\rm 2} \\ \rho \; g{\rm 3} \end{array} \! \right)$$ (2)

and the energy equation

$$\frac{\partial \rho e{\rm ik}}{\partial t} + \frac{\partial... ... \; v{\rm 1} + g{\rm 2} \; v{\rm 2} + g{\rm 3} \; v{\rm 3} ) .$$ (3)

In addition, there are equations for the 3D tensor viscosity and the non-local radiation transport.