The Compressible Potential Flow Model node adds equations for time-dependent or stationary modeling of compressible potential flow. The model will solve for the mean flow velocity potential and the density. The pressure and the velocity field are defined from these dependent variables.

For the Ratio of specific heats γ (dimensionless) select From material (the default) or User defined. For the User defined option the default value is 1.4.

Enter a Force potential ψ (SI unit: J/kg). To model a domain force or domain source acting on the fluid.

Select the Calculate temperature option it you need to also calculate the temperature field in the fluid. If this is selected, you also need to specify the Specific gas constant Rs (SI unit: J/(kg·K)). Select From material (the default) or User defined. Enabling this calculates the temperature according to

where pA is the pressure and ρ the density in the fluid.

Depending on the material selected in the Materials node for the fluid (typically Air) the Model Inputs may be active. Per default the Absolute pressure is taken from the model itself (grayed out). If the Calculate temperature option is enabled the Temperature is also taken from the model (grayed out). This will give a physically consistent solution. In both cases, you can click the Make All Model Inputs Editable icon to enter a user defined expression.