In FLUENT, if you choose to define the density using the ideal gas law for an incompressible flow, the solver will compute the density as
|=||the universal gas constant|
|=||the molecular weight of the gas|
In this form, the density depends only on the operating pressure and not on the local relative pressure field.
Density Inputs for the Incompressible Ideal Gas Law
The inputs for the incompressible ideal gas law are as follows:
Specify the incompressible ideal gas law individually for each material that you want to use it for. See Section 8.3.7 for information on specifying the incompressible ideal gas law for mixtures.
Define Operating Conditions...
| By default, operating pressure is set to 101325 Pa. The input of the operating pressure is of great importance when you are computing density with the ideal gas law. See Section
8.14 for recommendations on setting appropriate values for the operating pressure.