Accession Number : AD0661956

Title :   SOME EFFECTS OF WIND TUNNEL INTERFERENCE OBSERVED IN TESTS ON TWO-DIMENSIONAL AEROFOILS AT HIGH SUBSONIC AND TRANSONIC SPEEDS,

Corporate Author : ADVISORY GROUP FOR AERONAUTICAL RESEARCH AND DEVELOPMENT PARIS (FRANCE)

Personal Author(s) : Pearcey,H. H. ; Sinnott,C. S. ; Osborne,J.

Report Date : MAR 1959

Pagination or Media Count : 76

Abstract : The report discusses the interference effects for the slotted working sections now in use. The magnitudes of the blockage and lift effect corrections are deduced for the ratio of model chord to tunnel height normally used. It is shown that a simple adaptation to reduce the open area of the walls would reduce both corrections to insignificant proportions simultaneously, but would give a reduced choking Mach number (<1.0) and possibly introduce wake interference effects for severely separated flows. The observed trends in the variation of the blockage effects for other ratios of model chord to tunnel height differ from those predicted theoretically. It is suggested that wake interference effects can significantly influence the manner in which separated flows develop with increasing incidence or Mach number, particularly for walls of small open area. Examples are also given of effects of distortions in the local supersonic flow, which are most noticeable for walls with relatively large open areas. (Author)

Descriptors :   (*AIRFOILS, MODEL TESTS), (*WIND TUNNELS, INTERFERENCE), (*SUBSONIC FLOW, AIRFOILS), (*TRANSONIC FLOW, AIRFOILS), DRAG, FLOW SEPARATION, LIFT, WALLS

Subject Categories : Aerodynamics
      Test Facilities, Equipment and Methods
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE