Lift Hysteresis of an Oscillating Slender Ellipse.

Abstract

A theoretical investigation has been made to determine the variation of lift with time on a slender elliptic cylinder oscillating in pitch. The development of the unsteady two-dimensional laminar boundary layer over the surfaces of the pitching ellipse is calculated and the periodic variation of lift is determined by matching the rate at which boundary layer developed vorticity is shed into the wake with the time rate of change of circulation about the ellipse. The effects of mean angle-of-attack and oscillation frequencies on lift hysteresis loops are determined. It is shown that the hysteresis loops change direction for mean angles of attack greater than that corresponding to maximum steady state lift. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Sep 30, 1977
Accession Number
ADA049343

Entities

People

  • J. C. Williams Iii
  • W. Donald Johnson

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Advanced Electronics
  • C4I
  • Space

DTIC Thesaurus Topics

  • Boundary Layer
  • Boundary Layer Flow
  • Coordinate Systems
  • Differential Equations
  • Equations
  • Flow
  • Fluid Dynamics
  • Incompressible Flow
  • Laminar Boundary Layer
  • Oscillation
  • Periodic Variations
  • Potential Flow
  • Stagnation Point
  • Steady Flow
  • Steady State
  • Thickness
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Aerodynamics/Aeronautics.
  • Control Systems Engineering.
  • Fluid Dynamics.