AN ACTUATOR DISC THEORY FOR THE SHED WAKE AT LOW TIP SPEED RATIOS

Abstract

A model of the flow through a helicopter rotor, suitable for estimating shed wake effects in hovering and at low tip speed rations, is described. The method leads to the same result for the aerodynamic damping of blade bending oscillations as more complex theories. It is shown that the damping of small natural oscillations is to a first order unaffected by tip speed ratio. Interharmonic couplings, arising out of the convection of the shed vorticity parallel to the rotor disc, prove to be quite important, especially if resonance occurs. Also, in the presence of strong interharmonic coupling, the effective lift curve slope cannot be considered as a universal parameter, independent of the harmonic content of the blade motion.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1965
Accession Number
AD0637744

Entities

People

  • J. P. Jones

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Air Platforms
  • Weapons Technologies

DTIC Thesaurus Topics

  • Aerodynamic Forces
  • Aircrafts
  • Computational Fluid Dynamics
  • Computational Science
  • Convection
  • Differential Equations
  • Equations
  • Flow
  • Fluid Dynamics
  • Fluid Mechanics
  • Frequency
  • Ground Effect
  • Ground Effect Machines
  • Partial Differential Equations
  • Resonant Frequency
  • Short Takeoff Aircraft
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Control Systems Engineering.