Mach Wave Elimination in Supersonic Jets

Experimental results are presented on a method that eliminates Mach waves from the exhaust of supersonic jets and, hence, that removes a strong component of supersonic jet noise. Elimination is achieved by surrounding the jet with an annular stream at prescribed velocity and temperature so that all turbulent motions become intrinsically subsonic. No mechanical suppressors are used. Implementation of the technique in a typical turbofan engine is estimated to increase takeoff thrust with minimal impact on overall fuel consumption.

[1]  Reduction of noise from supersonic jet flows , 1970 .

[2]  John M. Seiner,et al.  Relationship between the instability waves and noise of high-speed jets , 1991 .

[3]  R. Dibble,et al.  TIME EVOLUTION OF THE SHEAR LAYER OF A SUPERSONIC AXISYMMETRIC JET , 1991 .

[4]  John M. Seiner,et al.  Mach wave emission from a high-temperature supersonic jet , 1993 .

[5]  Dimitri Papamoschou,et al.  Visual observations of supersonic transverse jets , 1993 .

[6]  R. Dibble,et al.  Time evolution of the shear layer of a supersonic axisymmetric jet at matched conditions , 1990 .

[7]  H. K. Tanna,et al.  Coannular jets - Are they really quiet and why , 1980 .

[8]  H. T. Nagamatsu,et al.  Characteristics of Multitube Multishroud Supersonic Jet Noise Suppressor , 1972 .

[9]  M. Nagai.  Mechanism of Pseudo-shock Wave in Supersonic Jet , 1983 .

[10]  Christopher K. W. Tam,et al.  Sound generated by instability waves of supersonic flows. Part 1. Two-dimensional mixing layers , 1984, Journal of Fluid Mechanics.

[11]  Dimitri Papamoschou,et al.  STRUCTURE OF THE COMPRESSIBLE TURBULENT SHEAR LAYER , 1989 .

[12]  Dimitri Papamoschou,et al.  Analysis of partially mixed supersonic ejector , 1996 .

[13]  Christopher K. W. Tam,et al.  Sound generated by instability waves of supersonic flows. Part 2. Axisymmetric jets , 1984, Journal of Fluid Mechanics.

[14]  D. K. Mclaughlin,et al.  Experiments on the instability waves in a supersonic jet and their acoustic radiation , 1975, Journal of Fluid Mechanics.

[15]  D. K. Mclaughlin,et al.  Experiments on the flow and acoustic properties of a moderate-Reynolds-number supersonic jet , 1982, Journal of Fluid Mechanics.

[16]  John M. Seiner,et al.  Supersonic jet noise and the high speed civil transport , 1989 .

[17]  D. Papamoschou,et al.  Evolution of large eddies in compressible shear layers , 1997 .

[18]  Paul E. Dimotakis,et al.  Experiments in nonreacting compressible shear layers , 1991 .

[19]  R. W. Paterson,et al.  Supersonic nozzle mixer ejector , 1992 .