Author: Clarence Albert Pierce
Publisher:
Published: 1952
Total Pages: 49
ISBN-13:
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An experimental investigation was conducted in the University of Michigan Supersonic Wind Tunnel to explore the main characteristics of the flow and pressure field generated by a supersonic jet directed at 90 deg to the body into the 1.90-Mach-number tunnel stream. In particular, a study was made of the spreading characteristics of the jet and its gross effect on the normal fore, drag, and moment of the cone-cylinder body, from which the jet issued. The phenomenon was investigated as a function of the pressure ratio, P sub o/P sub s (jet stagnation pressure to tunnel static pressure), angle of attack of the body, and jet-nozzle geometry. Within a relatively short distance from the exit, the normal jet was turned in the direction parallel to the free stream even at pressure ratios of over 50. Simultaneously, it spread in all directions, mixing violently with the free stream. Optical evidence suggests that fringes of the jet are in contact with the cylinder. This may have practical implications for the use of hot side-control jets on bodies. The interaction resulted in regions of both high and low pressure over the body. The normal force on the body was decreased below the nominal jet side-thrust value, and the drag was increased above the no-jet value. A moment which depends on the geometry, particularly the length of the body, was generated about the nominal center of gravity of the body.
