Definitions
Key dimensionless parameters computed by flow_state.
Speed of Sound
The speed of sound in a perfect gas:
\[
a = \sqrt{\gamma R T}
\]
See Gas Properties for values of \(\gamma\) and \(R\).
Mach Number
The ratio of flow velocity to the local speed of sound:
\[
M = \frac{U}{a}
\]
Reynolds Number
The unit Reynolds number (Reynolds number per unit length):
\[
\text{Re}_1 = \frac{\rho U}{\mu}
\]
where \(\mu\) is the dynamic viscosity. See Transport Models for viscosity laws.
The Reynolds number based on a reference length \(L\):
\[
\text{Re}_L = \text{Re}_1 \cdot L = \frac{\rho U L}{\mu}
\]