Control of Wake Structure Behind and Oscillating Airfoil

Abstract

The initiation, development, and shedding of vortices induced by sinusoidal airfoil motions were examined in the airfoil wake across a range of independent forcing parameters. Then, the interactions of these wakes with a following or trailing airfoil were studied. Coherent, phase-dependent, tandem vortex wake structures emerged from the shedding vorticity of the UPSTREAM OSCILLATING AIRFOIL. Consistent interactions of the vortex wake with a trailing airfoil were revealed with both the multiple-exposure, phase-locked, flow visualization measures and the time-dependent surface pressure measurements. Impingement of the tandem vortex wake upon the trailing airfoil produced unsteady pressure distributions resulting in very transient loading. Similar effects in unsteady loading were observed when an auto-rotating flat plate was used to create a vortex-dominated wake. These finding suggest that a consistent, structured wake produced by unsteady separation might be used to produce desired lift characteristics on a trailing, lifting surface. Keywords: Flow visualization, Dynamic loads, Vortices.

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Document Details

Document Type
Technical Report
Publication Date
Jul 08, 1986
Accession Number
ADA227904

Entities

People

  • H. E. Helin
  • M. C. Robinson
  • M. W. Luttges

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Aerodynamic Characteristics
  • Availability
  • Boundary Layer
  • Convection
  • Dynamic Loads
  • Dynamics
  • Flow Visualization
  • Fluid Dynamics
  • High Pressure
  • Leading Edges
  • Measurement
  • Pressure Distribution
  • Pressure Measurement
  • Reynolds Number
  • Static Pressure
  • Trailing Edges
  • Vortex Shedding

Fields of Study

  • Physics

Readers

  • Fluid Mechanics and Fluid Dynamics.