Local and Global Resonances in Heated 2-D Jets

Abstract

The connection between local and global stability properties of free shear flows was investigated. For 2-D inviscid jets, absolute instability was found for ratios of jet to ambient density below 0.9. Low wake heating (density) eliminates all local absolute instability. In 2-D heated jets, experiments showed that local absolute instability does lead to global instability and self- excitation at a density ratio of 0.9. The flow was documented with Schlieren and mean velocity and temperature measurements. The global linear stability of a slowly diverging inviscid shear flow has been theoretically analyzed by WKB methods. Global characteristics are found, under certain assumptions, to be determined by a region where the absolute frequency of the mode with zero group velocity has a saddle. (edc)

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1989
Accession Number
ADA221671

Entities

People

  • Ming H. Yu
  • Peter A. Monkewitz

Organizations

  • University of California, Los Angeles

Tags

Communities of Interest

  • Air Platforms
  • Sensors
  • Space

DTIC Thesaurus Topics

  • Boundary Layer
  • Buoyancy
  • Computational Fluid Dynamics
  • Computational Science
  • Data Acquisition
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Flow
  • Fluid Mechanics
  • Measurement
  • Near Field
  • Reynolds Number
  • Shear Flow
  • Strouhal Number
  • Turbulent Mixing
  • Two Dimensional
  • Viscous Flow

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Fluid Mechanics and Fluid Dynamics.
  • Thermal Physics or Thermal Science.