Use of Two - Dimensional Unsteady Flow Theory with Low Aspect - Ratio Blades,

Abstract

It is known that if two-dimensional airfoil theory is used to calculate the mean forces on a marine propeller blade, the answer obtained is likely to over-estimate the true answer by a factor of typically three. It is shown that when unsteady forces (at shaft-rate or blade-rate) are being calculated, the use of unsteady two-dimensional airfoil theory is much more acceptable, for being associated with errors of about 60% for shaft-rate forces and 25% for blade-rate forces. It is pointed out that the more accurate unsteady lifting-surface theory is prohibitively expensive for use regularly as a design tool, and further, that the accuracy of the answer may be limited in any case by the accuracy of the measured wake data. (Author)

Document Details

Document Type
Technical Report
Publication Date
May 01, 1973
Accession Number
AD0771941

Entities

People

  • M. T. Murray

Organizations

  • Admiralty Research Laboratory

Tags

DTIC Thesaurus Topics

  • Accuracy
  • Aspect Ratio
  • Blades
  • Engineering
  • Errors
  • Flow
  • Lifting Surfaces
  • Marine Propellers
  • Mechanical Engineering
  • Propeller Blades
  • Propellers
  • Propulsion Systems
  • Two Dimensional
  • Unsteady Flow

Fields of Study

  • Physics

Readers

  • Aerodynamics/Aeronautics.
  • Fluid Mechanics and Fluid Dynamics.
  • Maritime Combat Support and Expeditionary Logistics.