Effectiveness of jet location on mixing characteristics inside a cavity in supersonic flow

Takahiro Ukai, Hossein Zare-Behtash, Erinc Erdem, Kin Hing Lo, Konstantinos Kontis, Shigeru Obayashi

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)


The incorporation of cavities within supersonic combustion chambers is an effective means of slowing down the flow for fuel injection and consequent stable combustion. Understanding the flow physics associated with such flows, especially with the injection of a gas to replicate fuel injection, are essential for the optimum design of supersonic propulsion mechanisms. An experimental investigation was performed on a rectangular open cavity with upstream injection model in a Mach number of 1.9 using a trisonic indraft wind tunnel. A rectangular open cavity of dimensions L/D = 5, 100. mm in length (L) and 20. mm deep (D), was adopted, and it was embedded into the lower wall of the test section. An air jet with a jet-to-freestream momentum flux ratio of J = 1.2, 2.7 and 5.3 was injected upstream of the cavity. To evaluate the effect on mixing and flow stability the jet position, measured from the front edge of the cavity, was varied between 0.1. L and 1. L. The flow field was visualized using schlieren photography, particle image velocimetry, and oil flow measurements. It is found that the mixing characteristic within the cavity when the jet is positioned 0.1. L is enhanced independent on the J value because the turbulence intensity of the flow velocity within the cavity is strongly influenced by the jet interaction which lifted the flow from the floor of the cavity compared to the other jet positions. However, the flow over the cavity is unstable at all jet positions. The separation shock formed at the front edge of the cavity oscillates significantly for the case where the jet is located at 0.1. L because the separation shock location coincides with the compression shock behind the jet.

Original languageEnglish
Pages (from-to)59-67
Number of pages9
JournalExperimental Thermal and Fluid Science
Publication statusPublished - 2014 Jan


  • Cavity
  • Mixing characteristic
  • Scramjet
  • Supersonic injection

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Nuclear Energy and Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


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