Active Control of Supersonic Impinging Jets

Abstract

Experimental studies of supersonic impinging jet flows suggest that they are greatly influenced by the flow-acoustic interactions through a feedback mechanism. The self-sustained oscillations of the jet column observed in theses flows result in high velocities in the ambient medium induced by the large-scale coherent vortical structures in the jet shear layers. As a consequence, the suck down force on the surface from which the jet is issuing can reach as high as 60% of the primary jet thrust. In addition, the overall sound pressure level (OASPL), increase significantly relative to a free jet. To alleviate these undesirable flow and acoustic characteristics, a novel control technique using supersonic microjets is demonstrated. Sixteen supersonic microjets are placed around the circumference of the main jet at the nozzle exit to disrupt the feedback mechanism. As a result, significant lift loss recovery(-50%) and reduced near field OASPL (-7dB) are observed.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2001
Accession Number
ADP011106

Entities

People

  • A. Krothapalli
  • Chung-You Shih
  • F. Alvi
  • R. Elavarasan

Organizations

  • Florida State University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Acoustic Waves
  • Aircrafts
  • Airframes
  • Boundary Layer
  • Fighter Aircraft
  • Flow Fields
  • Fluid Dynamics
  • Fluid Mechanics
  • Frequency
  • Geometry
  • Insensitive Explosives
  • Jet Flow
  • Military Aircraft
  • Pressure Distribution
  • Short Takeoff Aircraft
  • Stratified Fluids
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

  • Acoustical Oceanography.
  • Fluid Mechanics and Fluid Dynamics.

Technology Areas

  • Hypersonics