Mach Wave Elimination
A new method for quieting high-speed jets
(U.S. Patents 5590520 and 5916127)


THE CONCEPT

EXPERIMENTAL SETUP

ACOUSTIC DATA

APPLICATION TO AEROENGINES

TECHNOLOGY EXCHANGE

FUTURE PLANS

SPONSORSHIP

PUBLICATIONS

PUBLICITY & AWARDS

TMWE- Jets with arcuate coflow

The eccentric jets produce very good downward noise reduction but the benefit declines with increasing azimuth angle.  As a result, the drop of peak noise in the 45-deg azimuth is only half that in the 0-deg azimuth (vertical).  An arcuate coflow nozzle has uniform flow thickness over its arc, therefore provides better noise reduction in the sideline direction.

We started testing these jets in Fall 2000.   The results presented here are preliminary.

Generic nozzle design

Crude first attempt, made of fiberglass

arcuate_nozzle_design.jpg (9183 bytes) fiberglass_arcuate_nozzle.jpg (12887 bytes)

I
nner nozzle: Mach 1.5; dia=12.7 mm (same as in all other experiments)

Outer nozzle:  Convergent; dia=25.4 mm; arc=240 deg.

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