Symposium on Compressible Free Mixing and Jet Noise Reduction

Axially Symmetrical Jet Mixing of a Compressible Fluid*

The corresponding laminar problem has been theoretically analyzed by Schlichting3 in 1933. Neither of these solutions, however, holds for finite opening, i.e. at a short distance from the opening. Kuethe,3 in 1935, extended Tollmien's results to the case of a two-dimensional jet issuing into a medium not at rest and also worked out an approximate method for'the computation of the velocity profi...

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 ...

Experimental and CFD Studies on the Effect of the Jet Position on Mixing Performance

Turbofan Jet Noise Reduction via Deflection of the Bypass Stream

We describe a parametric experimental study of noise reduction via de ection of the secondary stream in dual-stream jets. The jets simulated the exhaust of turbofan engines with bypass ratios 4.5 and 6.0. The secondary (bypass) stream was de ected downward by means of vanes installed inside the bypass duct. Variables included the number of vanes, vane angle of attack, azimuthal placement, and a...

The Reduction of Supersonic Jet Noise Using Pulsed