Book Description

A cold flow-field study of a rapid expansion, Mach 4.73, two-dimensional multiple nozzle array has been carried out in the hypersonic wind Tunnel. The nozzles are of the type used in a gas dynamic laser where the quality of the downstream flow field is important. The report examines the uniformity of the flow field in such a multiple nozzle array. Tests were conducted at supply conditions of 45 psia and 540 deg R. Pitot pressure, static pressure, and total temperature were measured along the axial, vertical, and horizontal centerlines within the nozzle and 21 nozzle exit heights downstream. Shadowgraph pictures provided qualitative flow field observations. The shock structure consisted of sidewall shocks, nozzle trailing edge shocks, and nozzle throat shocks. Viscous phenomena consisted of the boundary layers on the sidewalls and contoured walls, as well as the turbulent wakes caused by the trailing edges of the center nozzle blades. Mach number, static temperature, static density, and velocity profiles are presented. This flowfield information is useful to the prediction of the degradation of beam quality resulting from the non-homogeneity of a gas-dynamic-laser flowfield.