Enhanced mixing and noise reduction by auxiliary jets

Charles H. Berman, Otto P. Andersen, Edward L. Dreizin

Research output: Contribution to journalArticlepeer-review


The objective was to determine the capability of small auxiliary jet flows which impinge on a supersonic jet to enhance mixing between the main jet and the surrounding ambient medium and to determine the effectiveness of this approach to reduce the jet noise. Significant reductions in the far field jet noise were obtained over a range of auxiliary jet pressures and flow rates when used in conjunction with an acoustically lined ejector. A variety of auxiliary jet and ejector configurations and operating conditions were studied. The best results, obtained for auxiliary jets with mass flows of 6.6% of the main jet flow and confined with ejectors that were 8 times the main jet diameter in length, yielded peak to peak noise reductions ranging from 11 to 16 dB, depending on measurement angle. The total auxiliary jet flow momentum appears to be the most important parameter controlling the observed phenomenon.

Original languageEnglish (US)
Pages (from-to)491-496
Number of pages6
JournalAmerican Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED
StatePublished - 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Engineering


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