UNIVERSITY OF CALIFORNIA, IRVINE
JET AEROACOUSTICS LABORATORY

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We are working on innovative techniques to suppress jet noise from engines of subsonic and supersonic aircraft. Technology developed and patented at UCI includes the Mach Wave Elimination method and the Fan Flow Deflection technique.  The fundamental principle is reduction of the convective Mach number and turbulent kinetic energy of turbulence that causes intense downward noise.   This is achieved by concentrating some of the quieter fan flow underneath the noisy core stream of a turbofan engine.  The re-orientation of the fan flow is achievable using using offset nozzles or fan flow deflectors.  Experiments are conducted in unique small-scale facilities that enable testing of turbofan exhaust flows at realistic conditions.   Computations, under the guidance of Prof. Feng Liu, provide estimates of aerodynamics performance and turbulence statistics in the jet plume. Research has been sponsored by NASA and Goodrich Corp.  

Recent publications:

Papamoschou, D., "Fan Flow Deflection in Simulated Turbofan Exhaust," AIAA Journal, Vol. 44, No.12,   2006, pp. 3088-3097. (PDF)
Papamoschou, D. and Liu, F., "Aerodynamics of Fan Flow Deflectors for Jet Noise Suppression, "   Journal of Propulsion and Power, Vol. 24, No.3, 2008, pp. 437-445.(PDF)
Papamoschou, D., "Pylon Based Jet Noise Suppressors," AIAA Journal, Vol. 47, No.6,  2009, pp. 1408-1420. (PDF)

Patents:

Papamoschou, D. "Method of Eliminating Mach Waves from Supersonic Jets," U.S. Patent 5,590,520; issued 1/7/97.
Papamoschou, D. "Method of Eliminating Mach Waves from Supersonic Jets," U.S. Patent 5,916,127; issued 6/29/99.
Papamoschou, D. "Jet Engine Noise Suppressor," U.S. Patent No. 7,293,401;  issued 11/13/07

 

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Illustration of fan flow deflection using internal vanes or external wedge.

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Testing of external wedge (top) and its more realistic variant, pylon flaps (bottom) , in a subsonic nozzle with bypass ratio 8.

 

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Precision installation of deflector vane (shown without fan duct) of a supersonic nozzle with bypass ratio 2.7. 

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