Jet - Definition and Overview

See also: Jet (disambiguation)

A jet is a stream of fluid produced by discharge through an orifice into free space.

Since gases are compressible fluids, the velocity attained by a jet of gas cannot be determined by Bernoulli's principle. Instead, if one uses adiabatic expansion from P₁ to P₂ in a properly shaped nozzle, the ideal velocity of a gas jet is:

<math>v=8\sqrt{(RT_1/z) (1-(P_2/P_1)^z)} <math>

R is the common gas constant

T₁ is the absolute temperature at pressure P₁

z is <math>\begin{matrix}{c_p - c_v \over c_p}\end{matrix}<math>

c_p is the specific heat at constant pressure

c_v is the specific heat at constant volume

z = 0.286 for air under 500 °C

z = 0.23 to 0.28 for most combustion products of fuels

See jet engine and jet aircraft.