Flow of Under-Expanded Supersonic Jets in Square and Round Tubes

摘要

The flow of a cold under-expanded supersonic air jet exhausting axially into round and square section tubes of various cross-sectional areas was investigated. A sonic and a Mach 2.2 nozzle of the same throat diameter were used. Static pressure distributions were obtained along the wall for the round and square tubes, and it is found that similar pressure distributions are obtained if the tubes are of similar cross-sectional areas. In this case, the flows visualized in the square tubes are taken to be representative of the flows in the round tubes. Three distinct types of flow are observed: unattached, attached, and oblique shock type flows. These can be obtained with various combinations of reservoir pressure and tube cross-sectional area.