# 7.15.1.7. Extension_Speed

Syntax

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

Scope

  Aria Region

Summary

  Activates an equation for extension speed, which is used by the level set equation (Level Set/CDFEM) to define the interface speed.

Description

  The only admissible value for Dof is `EXTENSION_SPEED`.

  Admissible values of Interp are .

  Admissible values of Term_n are `DEF`, `SRC`, and `XFER`.

  With the exception of `XFER` these terms are described in Generalized Conservation Equation.

  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 | –