where M* is the characteristic Mach number ( No unit)
M is the Mach Number ( No unit)
γ is the ratio of specific heat (No unit)
M∗ = V/a* = V/(γ×R×T* )^0.5
where V is the local flow velocity (m/s)
T∗ is the temperature at sonic condition (K)
R is the specific gas constant (0.287 KJ/kgK)
