Control of Two and Three-Dimensional Wake Instabilities from Bluff-Bodies.

Abstract

The detailed, instantaneous flow structure of the near-wake of a cylinder subjected to various classes of active (open-loop) and passive control has been characterized using both qualitative flow visualization and high-image-density particle image velocimetry (piv) developed in our laboratories. The first cinema PIV system allows acquisition of images that are highly resolved in both space and time. Concepts of timing of vortex formation, period-doubled patterns of vortices, and modulated and phase-locked systems of vortices are addressed for controlled oscillations of the cylinder. Three-dimensional patterns of instantaneous vorticity allow classification of the modes of response of the near-wake, providing a basis for formulating concepts for attenuation of vortex formation.

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Document Details

Document Type
Technical Report
Publication Date
Feb 28, 1995
Accession Number
ADA300250

Entities

People

  • Donald O. Rockwell

Organizations

  • Lehigh University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Applied Mechanics
  • Boundary Layer
  • Engineering
  • Flow
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Mechanics
  • Frequency
  • Mechanical Engineering
  • Mechanics
  • Oscillation
  • Particle Image Velocimetry
  • Particles
  • Pattern Recognition
  • Reynolds Number
  • Three Dimensional
  • Visualizations

Fields of Study

  • Physics

Readers

  • Control Systems Engineering.
  • Fluid Mechanics and Fluid Dynamics.

Technology Areas

  • Space
  • Space - Spacecraft Maneuvers