EXPERIMENTAL INVESTIGATION ON PERFORATED CONE-CYLINDER CONFIGURATIONS IN AXISYMMETRIC SUPERSONIC FLOW

Document Type : Original Article

Author

Research Scientist, National Institute for Scientific and Technical Creation, INCREST, Bd. Pacii 220,Bucharest Romania.

Abstract

An experimental investigation upon perforated cone-cylinder configurations (with vertex half angles of 21°, 22°30' and 25° , at Mach numbers of 1.38 , 1.79 & 2.23 ) was performed in the Romanian Trisonic Wind Tunnel. The results show that the total drag as well as the foredrag are affected in a positive way - especially below a Mach number depending on the vertex angle, on the porosity, on the plenum chamber volume and on the Reynolds number - by the occurence of a secondary ( inner ) flow and by its interaction with the main stream. The Schlieren pictures point out details of the complex phenomenon taking place, by indicating the disappearance of the expansion fan, which normally appears on the joint of a cone-cylinder body, as well as the occurence of a separation streamline between the passive blown flow and the oncoming stream. Drag reducing potential of the using of axisymmetric perforated configurations is demonstrated , provided that matching the outflow and inflow characteristics is mastered.

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