Lifting Surface Theory and Hydroelastic Instability

Abstract

A brief review is presented of the unsteady lifting surface theory and of the 'generalized lift operator' technique of inverting the 'downwash' integral equation. The integral equation approach is then employed to predice responses of various foils to pitching oscillations and to forward motion in a regular wave train. The agreement between theoretical predictions and experimental results is good for simple configurations without appendages, but not in the case of the AG(EH) configuration at low frequencies because the presence of the pod is not taken into account in the theoretical calculations. Although the attempt made to remove the spurious leading-edge singularity in the chordwise pressure distribution before inverting the integral equation is questionable, removal of the singularity after the inversion yields responses consistent with other theoretical and experimental trends.

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Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1973
Accession Number
AD0778351

Entities

People

  • M. R. Ali
  • S. Tsakonas
  • William Jacobs

Organizations

  • Stevens Institute of Technology

Tags

Communities of Interest

  • Air Platforms
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Aerodynamic Configurations
  • Airfoils
  • Aspect Ratio
  • Bessel Functions
  • Computer Programs
  • Computers
  • Frequency
  • Froude Number
  • Hydrodynamics
  • Hydrofoils
  • Kernel Functions
  • Pressure Distribution
  • Shape
  • Sweptback Wings
  • Three Dimensional
  • Two Dimensional
  • Unsteady Flow

Readers

  • Aerodynamics.
  • Approximation Theory.
  • Control Systems Engineering.