It's a bit like whistling. When you whistle, you purse your lips and force air out at speed and pressure. This creates whirls and eddies, which is what causes the noise.
If you were to exhale slowly, through wide open mouth, there wouldn't be any noise. That air would be doing what's called a linear flow, flow w/o any whirls and eddies.
A jet engine has tremendous amounts of air moving very fast at a fairly high pressure, so it too will have whirls and eddies, creating noise.
Also, there are moving parts wich make noise a bit like a car engine.
Thomas D Norum has written: 'Effects of simulated flight on the structure and noise of underexpanded jets' -- subject(s): Noise, Jet planes, Sound-waves 'A comparison of the noise produced by a small jet on a moving vehicle with that in a free jet' -- subject(s): Noise, Jet nozzles, Jet planes, Measurement
John G. Shearin has written: 'Investigation of jet-installation noise sources under static conditions' -- subject(s): Noise, Jet planes, Jet plane sounds, Aerodynamic noise
The jet noise? Like the Airplanes? Yes. My father loves the sound of a jet taking off and flying over you. It is his favorite part of all parades.
S. Paul Pao has written: 'A Correlation of mixing noise from coannular jets with inverted flow profiles' -- subject(s): Noise, Jet planes 'Spectral techniques in jet noise theory' -- subject(s): Spectral methods, Jet aircraft noise
Wing T. Chu has written: 'Turbulence measurements relevant to jet noise' -- subject(s): Turbulence, Free jets, Jet aircraft noise, Aerodynamic noise, Acoustics
Thrust .. and noise
Christopher Tam has written: 'Jet aeroacoustics' -- subject(s): Noise generators, Aeroacoustics, Gas jets, Jet aircraft noise, Turbulent mixing
George P Succi has written: 'Interaction of a turbulent-jet noise source with transverse modes in a rectangular duct' -- subject(s): Acoustic models, Noise, Jet planes, Aerodynamic noise
Royal Jet was created in 2003.
Jet Republic was created in 2008.
Sabre Jet was created in 1953.
Hellas Jet was created in 2002.