A Wavelet-Based Time-Frequency Analysis on the Supersonic Jet Noise Features with Chevrons

Fluidic Chevrons for Jet Noise Reduction

Chevron mixing devices are used to reduce noise from commercial separate-flow turbofan engines. Mechanical chevron serrations at the nozzle trailing edge generate axial vorticity that enhances jet plume mixing and consequently reduces far-field noise. “Fluidic chevrons” generated with air injected near the nozzle trailing edge create a vorticity field similar to that of the mechanical chevrons ...

Mach Wave Noise of a Supersonic Jet

Supersonic jets emit noise to the outside in form of Mach waves which are long, straight and have about equal angles. Experiments done by Oertel sen. visualized clearly these Mach waves and he publicized moreover that such Mach waves exist also inside the jet. Experimental and theoretical studies in the past did not allow a complete understanding of the phenomenon up to now, wherefore the need ...

Wavepacket models for supersonic jet noise

Gudmundsson and Colonius (J. Fluid Mech., vol. 689, 2011, pp. 97–128) have recently shown that the average evolution of low-frequency, low-azimuthal modal large-scale structures in the near field of subsonic jets are remarkably well predicted as linear instability waves of the turbulent mean flow using parabolized stability equations. In this work, we extend this modelling technique to an isoth...

Summary of "Supersonic Jet and Rocket Noise"

Simulation of Supersonic Military Aircraft Jet Noise

Background: There is a growing need to reduce significantly the noise generated by high-performance, supersonic military aircraft. The noise generated during takeoff and landing on aircraft carriers has direct impact on shipboard health and safety issues. Also, noise complaints are increasing as communities move closer to military bases or when there are changes due to base closures and realign...