Stagnation enthalpy

Stagnation enthalpy ( h t ) is the enthalpy of a flow at a stagnation point. It is the enthalpy at a stagnation point (zero velocity) if the flow is brought to a stop from velocity v .

Total enthalpy is defined at every point in a flow field. It 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 stagnation enthalpy at a stagnation point is identical to the total enthalpy everywhere in the flow field.

h t = h + v 2 2

where h is enthalpy, and v is velocity.

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.