A THEORY FOR UNSTEADY MOTIONS OF JET-FLAPPED THIN AIRFOILS

Abstract

A linearized model for the incompressible, in viscid, irrotational, and unsteady flow about a thin airfoil with jet-flap is formulated. The unsteady problems considered are the transient and oscillatory deflection of the jet, plunging and pitching of the airfoil, deflection of a blown-flap, and also the penetration of a sharp-edged gust. Justification is given for representation of the jet, in the limit of high speed, small thickness, and constant momentum flux strength, by a vortex sheet, across which there is a pressure difference proportional to the momentum-flux strength and inversely proportional to the local radius of curvature of the jet. The dynamic and kinematic interaction of the main stream with the vortex sheets representing the airfoil and jet are shown to be described by a coupled set of equations consisting of a third-order partial differential equation and a singular integral equation, along with appropriate boundary conditions. The properties of these equations and their relationship to classical unsteady thin-airfoil theory and steady jet-flap theory are discussed.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Sep 01, 1962
Accession Number
AD0407504

Entities

People

  • J. C. Erickson Jr.

Organizations

  • Cornell University

Tags

Communities of Interest

  • Air Platforms
  • Materials and Manufacturing Processes
  • Space

DTIC Thesaurus Topics

  • Aircrafts
  • Airfoils
  • Boundary Layer
  • Boundary Value Problems
  • Computational Fluid Dynamics
  • Computational Science
  • Difference Equations
  • Differential Equations
  • Equations
  • Fluid Dynamics
  • Fluid Mechanics
  • Hydrodynamics
  • Integral Equations
  • Partial Differential Equations
  • Pressure Distribution
  • Static Pressure
  • Steady State

Fields of Study

  • Physics

Readers

  • Aerodynamics/Aeronautics.
  • Fluid Dynamics.