# 7.15.1.10. Mass_Balance

Syntax

  Eq Mass_Balance for Associated DoF [{of} SpeciesName | {in} MaterialPhaseName | {ls} {a | b | c}] {on} MeshPart using Interp with {Term_0} … {Term_N}

Scope

  Aria Region

Summary

  The mass balance equation for porous media. See general porous flow information in Porous Flow Equations.

Description

  Admissible value for Dof are `PRESSURE`, `DENSITY`, `SATURATION`, and `MASS_FRACTION`.

  Admissible values of Interp are .

  Admissible values of Term_n are `MASS`, `LUMPED_MASS`, `ADV`, `UPWIND_ADV`, `DIFF`, `SRC`, and `XFER`.

  With the exception of `XFER` these terms are described in Porous Flow Equations.

  The Meshpart must be an active element block.

Parameter | Value | Default
--- | --- | ---
{of} | {of | species | subindex} | –
SpeciesName | string | –
{in} | {in | material_phase} | –
MaterialPhaseName | string | –
{ls} | {levelset_phase | ls} | –
Associated DoF | string | –
{on} | {@ | at | for | in | on | over} | –
MeshPart | string | –
Interp | string | –
{Term_n} | See Description | –