Stagnation enthalpy

Stagnation enthalpy is the enthalpy of a flow at a stagnation point. It is the enthalpy at a stagnation point if the flow is brought to a stop from velocity ${\displaystyle v}$.[1]

Total enthalpy (${\displaystyle h_{t}}$) is defined at every point in a flow field but stagnation enthalpy is only defined at a stagnation point. Total enthalpy is the sum of the enthalpy associated with the temperature at each point plus the enthalpy associated with the dynamic pressure at each point. Total enthalpy is the same at every point in a flow field so the enthalpy at a stagnation point is numerically equal to the total enthalpy everywhere in the flow field.

${\displaystyle h_{t}=h+{\frac {v^{2}}{2}}}$

where ${\displaystyle h}$ is enthalpy, and ${\displaystyle v}$ is velocity.[1]

Stagnation enthalpy has units of energy, such that if enthalpy is thought of as the energy associated with the temperature plus the energy associated with the pressure, the stagnation enthalpy adds a term associated with the kinetic energy of the fluid mass.