Accession Number : ADP006221

Title :   Experimental Investigation of Buffet Onset and Penetration on a Supercritical Airfoil at Transonic Speeds,

Corporate Author : DEUTSCHE FORSCHUNGSANSTALT FUER LUFT- UND RAUMFAHRT GOETTINGEN (GERMANY F R)

Personal Author(s) : Stanewsky, E. ; Basler, D.

Report Date : SEP 1990

Pagination or Media Count : 11

Abstract : An experimental investigation was carried out on the supercritical airfoil CAST 7/DOA1 to determine the influence of three parameters--Mach number, angle of attack and most of all Reynolds number--on the buffet process and especially on the shock oscillation frequency and amplitude. For this investigation, the model was equipped with regular pressure orifices, dynamic pressure transducers and hot-film sensors, the latter used to determine transition location and regions of separation. The flow field was observed by a holographic high-speed, real-time interferometer. Analysis of the results revealed that the buffet process is essentially driven by the interaction of the upper surface shock wave with the boundary layer, especially as it influences the development of the shock-induced separation bubble, and the resultant change in flow conditions at the airfoil trailing edge and that, within the domain of intensive buffet, the shock oscillation frequency decreases with Reynolds number while the amplitude increases.

Descriptors :   *SUPERCRITICAL AIRFOILS, *BUFFETING, TRANSONIC CHARACTERISTICS, ANGLE OF ATTACK, MACH NUMBER, SHOCK WAVES, OSCILLATION, FLOW SEPARATION, BUBBLES, AERODYNAMIC LOADING, WEST GERMANY.

Subject Categories : Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE