Unsteady Flow Past a NACA 0012 Airfoil Pitching at Constant Rates

Abstract

The dynamic stall process of a NACA 0012 airfoil undergoing a constant-rate pitching up motion is studied experimentally in a water towing tank facility. This study focuses on the detailed measurement of the unsteady separated flow in the vicinity of the leading and trailing edges of the airfoil. The measurements are carried out using the Particle Image Velocimity (PIV) technique. This technique provides the two-dimensional velocity and associated vorticity fields, at various instants in time, in the mid-span of the airfoil. Near the leading edge, large vortical structures emerge as a consequence of Van Dommelen and Shen type separation and a local vorticity accumulation. The interaction of these vortices with the reversing boundary layer vorticity initiates a secondary flow separation and the formation of a secondary vortex. The mutual induction of this counter-rotating vortex pair eventually leads to the ejection process of the dynamic stall vortex from the leading edge region.

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Document Details

Document Type
Technical Report
Publication Date
Apr 13, 1993
Accession Number
ADA265159

Entities

People

  • A. Krothapalli
  • Chung-You Shih
  • L. Van Dommelen
  • Luiz M. Lourenco

Organizations

  • Florida A&M University

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Boundary Layer
  • Computational Fluid Dynamics
  • Engineering
  • Flow Visualization
  • Fluid Dynamics
  • Fluid Flow
  • Fluid Mechanics
  • Hydrodynamics
  • Leading Edges
  • Measurement
  • Mechanical Engineering
  • Reynolds Number
  • Trailing Edges
  • Turbulent Mixing
  • Two Dimensional
  • Unsteady Flow
  • Vortices

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Mechanical Engineering/Mechanics of Materials.