An explanation for the phase lag in supersonic jet impingement

Joel L. Weightman, Omid Amili, Damon Honnery, Julio Soria, Daniel Edgington-Mitchell

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


For the first time, a physical mechanism is identified to explain the phase lag term in Powell's impinging feedback loop equation (Powell, J. Acoust. Soc. Am., vol. 83 (2), 1988, pp. 515-533). Ultra-high-speed schlieren reveals a previously unseen periodic transient shock in the wall jet region of underexpanded impinging flows. The motion of this shock appears to be responsible for the production of the acoustic waves corresponding to the impingement tone. It is suggested that the delay between the inception of the shock and the formation of the acoustic wave explains the phase lag in the aeroacoustic feedback process. This suggestion is quantitatively supported through an assessment of Powell's feedback equation, using high-resolution particle image velocimetry and acoustic measurements.

Original languageEnglish (US)
Pages (from-to)815R11-815R111
JournalJournal of Fluid Mechanics
StatePublished - Mar 25 2017

Bibliographical note

Publisher Copyright:
© 2017 Cambridge University Press.


  • aeroacoustics
  • flow-structure interactions
  • jet noise


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