Fluid model
===========

Enabling the fluid solver and specifying fluid model options.
The following inputs must be preceded by the given to the fluid solver e.g., "fluid."

+------------------------------------------+----------------------------------------------------------+--------+----------+
|                                          | Description                                              |  Type  | Default  |
+==========================================+==========================================================+========+==========+
| solve                                    | Specify the names of the fluids or None to disable the   | String |  None    |
|                                          | fluid solver. The name assigned to the fluid solver is   |        |          |
|                                          | used to specify fluids inputs.                           |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| molecular_weight                         | Value of constant fluid molecular weight                 |  Real  |    0     |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| viscosity                                | Specify which viscosity model to use for fluid           | String |  None    |
|                                          | [required]. Available options include:                   |        |          |
|                                          |                                                          |        |          |
|                                          | * 'constant' for constant viscosity model                |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| viscosity.constant                       | Value of constant fluid viscosity [required if           |  Real  |  0       |
|                                          | viscosity_model='constant'].                             |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| specific_heat                            | Specify which specific heat model to use for fluid       | String |  None    |
|                                          | [required if advect_enthalpy]. Available options         |        |          |
|                                          | include:                                                 |        |          |
|                                          |                                                          |        |          |
|                                          | * 'constant' for constant specific heat model            |        |          |
|                                          | * 'mixture' required when fluid is a mixture of species  |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| specific_heat.constant                   | Value of constant fluid specific heat [required if       |  Real  |  0       |
|                                          | specific_heat_model='constant'].                         |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| thermal_conductivity                     | Specify which thermal conductivity model to use for      | String |  None    |
|                                          | fluid [required if advect_enthalpy=1]. available         |        |          |
|                                          | options include:                                         |        |          |
|                                          |                                                          |        |          |
|                                          | * 'constant' for constant thermal conductivity model     |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| thermal_conductivity.constant            | Value of constant fluid thermal conductivity [required   |  Real  |  0       |
|                                          | if thermal_conductivity_model='constant'].               |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| thermodynamic_pressure                   | Value of the thermodynamic pressure [required if the     |  Real  |  0       |
|                                          | constraint type is IdealGasClosedSystem]                 |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| reference_temperature                    | Value of the reference temperature used for specific     |  Real  |  0       |
|                                          | enthalpy                                                 |  Real  |  0       |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| species                                  | Specify which species can constitute the fluid phase     | String |  None    |
|                                          | [defined species must be a subset of the species.solve   |        |          |
|                                          | arguments]                                               |        |          |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| newton_solver.absolute_tol               | Define absolute tolerance for Damped-Newton solver       |  Real  |  1.e-8   |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| newton_solver.relative_tol               | Define relative tolerance for Damped-Newton solver       |  Real  |  1.e-8   |
+------------------------------------------+----------------------------------------------------------+--------+----------+
| newton_solver.max_iterations             | Define max number of iterations for Damped-Newton solver |  int   |  500     |
+------------------------------------------+----------------------------------------------------------+--------+----------+

Below is an example for specifying fluid solver model options.

.. code-block:: none

   fluid.solve = my_fluid

   fluid.viscosity = constant
   fluid.viscosity.constant = 1.8e-5

   fluid.reference_temperature = 298.15

   fluid.thermal_conductivity = constant
   fluid.thermal_conductivity.constant = 0.024

   fluid.specific_heat = mixture

   fluid.species =  O2  CO  CO2
