# GAS_KINETIC_MODEL

Specifies a gas kinetic model for the advective_diffusive multifield type.

## Type

AcuSolve Command

## Syntax

GAS_KINETIC_MODEL("name") {parameters...}

## Qualifier

User-given name.

## Parameters

- geometrical_configuration_index (integer) >=0 <=2 [=1]
- An integer value indicating the type of molecular configuration. If the value is 0, the molecule is a single atom. If it is 1 the molecule is linear. Finally, if it is 2, the molecule is nonlinear.
- Lennard_Jones_potential_well_depth (real) [=97.530]
- The Lennard-Jones potential well depth of the gas in Kelvin.
- Lennard_Jones_collision_diameter (real) [=3.621]
- The Lennard-Jones collision diameter of the gas in Angstroms.
- dipole_moment (real) [=0.0]
- The dipole moment of the gas in Debye.
- Polarizability (real) [=1.760]
- The polarizability in cubic Angstroms.
- rotational_relaxation_collision_number (real) [=4.0]
- The rotational relaxation collision number at 298 Kelvin.
- molecular_weight (real) [=0.028013]
- Molecular weight of the gas.

## Description

This command sets kinetic model molecular parameters for each gas. Gas kinetic model
is used to calculate viscosity, conductivity, and mass diffusion coefficients for
each model. This model should be referred to in the
MATERIAL_MODEL of the gas. Below is an example to set
parameters for
Nitrogen:

```
GAS_KINETIC_MODEL( "N2" ) {
geometrical_configuration_index = 1
molecular_weight = 0.028013
Lennard_Jones_potential_well_depth = 97.530
Lennard_Jones_collision_diameter = 3.621
dipole_moment = 0.0
polarizability = 1.760
rotational_relaxation_collision_number = 4.000
}
VISCOSITY_MODEL( "N2" ) {
type = gas_kinetic
}
CONDUCTIVITY_MODEL( "N2" ) {
type = gas_kinetic
turbulent_prandtl_number = 0.91
}
```

If the species_transport equation is getting solved, gas kinetic diffusivity can be
set as:

```
DIFFUSIVITY_MODEL( "N2" ) {
type = gas_kinetic
}
```

If the multi_field equation type advective-diffusive is getting solved, gas kinetic
diffusivity should be set using
FIELD_INTERACTION_MODEL:

```
FIELD_INTERACTION_MODEL( "Mixture" ) {
type = advective_diffusive
diffusion_matrix_type = gas_kinetic
}
```