### 2.4.3. Inlet (Supersonic)

Supersonic inlet boundaries can be specified where the local Mach number is everywhere greater than unity. Supersonic boundary conditions can only be imposed if the `Total Energy` model is employed, and the fluid is either an ideal gas, a real fluid, or a general fluid whose density is a function of pressure.

#### 2.4.3.1. Mass and Momentum

At a supersonic inlet boundary, the required settings depend on the choice of Mass and Momentum > Option, as shown in Table 2.1: Supersonic Inlet Settings:

Table 2.1: Supersonic Inlet Settings

Mass and Momentum Option | Required Information
--- | ---

Normal Speed & Pressure

- Relative static pressure

- Normal speed

- Static or total temperature

Normal Speed & Total Pressure

- Relative total pressure

- Normal speed

- Static or total temperature or total enthalpy

Cart. Vel. & Pressure

- Relative static pressure

- Cartesian velocity components

- Static or total temperature

Cart. Vel. & Total Pressure

- Relative total pressure

- Cartesian velocity components

- Static or total temperature or total enthalpy

Cyl. Vel. & Pressure

- Relative static pressure

- Cylindrical velocity components

- Static or total temperature

Cyl. Vel. & Total Pressure

- Relative total pressure

- Cylindrical velocity components

- Static or total temperature or total enthalpy

Static and Total Pressure

- Relative static pressure

- Relative total pressure

- Total temperature

Note: For rotating domains, the total pressure is interpreted with respect to the stationary frame of reference.

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