Flow in the base region of flat bodies

Abstract

A considerable number of theoretical and experimental papers has been devoted in recent years to studying the flow details in the base region which were not included in the Chapman-Korst scheme. The authors obtained new data supplementing the known facts, or altering the conception about the substance of certain phenomena (the origination of the edge shock, for example). Results are presented below of experimental investigations of the flow configuration in the base region of flat bodies, and the fundamental parameters governing the difference between the flow behind pointed and blunt bodies are examined. The experiments were conducted in the wind tunnel of the Moscow State University Institute of Mechanics in the M=0.3–3.8 Mach number range. The Reynolds numbers, referred to 0.1 m and computed by means of the free-stream parameters, varied between 2·106 and 3·106. The flow behind a wedge (with a 45° vertex angle and 0.025 m altitude) mounted on a plate 0.2 m wide and 0.4 m long was investigated. The flow was studied in the near wake on wedges withapex half-angles Θ=15, 20, and 30°, width 0.2, altitude of the rear section 0.05 m, and a cylinder of the same width and 0.05 m diameter. The models were mounted in the center of the working section by using slender lateral pylons fastened to the perforated walls of the tunnel. A strip of emery paper was glued to turbulize the boundary layer on the models. The pressure in the base domain was measured by using total and static pressure detectors (1.2 mm outer diameter) mounted on a traversing gear.