Accession Number : ADA130475

Title :   A New Method of Estimating Wind Tunnel Wall Interference in the Unsteady Two-Dimensional Flow (Nouvelle Methode D'Estimation de la Perturbation des Ecoulements Instationnaires par les Parois d'une Soufflerie).

Descriptive Note : Aeronautical note,

Corporate Author : NATIONAL AERONAUTICAL ESTABLISHMENT OTTAWA (ONTARIO)

Personal Author(s) : Sawada,H

PDF Url : ADA130475

Report Date : Jan 1983

Pagination or Media Count : 61

Abstract : A new method of estimating wall interference in unsteady flow is presented. This method is valid for subcritical flow within the accuracy of the linearized small disturbance theory. The main feature of the method is the use of measured pressure along lines in the flow direction near the tunnel walls. This method is particularly effective in a tunnel with ventilated walls because it does not require the representation of wall characteristics with unreliable mathematical expressions. Results of some numerical examples indicate that the new method produces satisfactory results except for cases when the reduced frequencies are close to the tunnel resonance frequencies. For the case of an airfoil in pitching motion, the method has been used to correct the amplitude of the angle attack and the time lag in the motion. (Author)

Descriptors :   *Unsteady flow, *Wind tunnels, Interference, Walls, Subsonic flow, Two dimensional flow, Estimates, Boundary value problems, Resonance, Pressure distribution, Time dependence, Airfoils, Oscillation, Pitch(Motion), Angle of attack, Corrections, Canada

Subject Categories : Numerical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE