Outflow of an unexpanded jet into counter supersonic and subsonic flows

Abstract

The article gives the results of an experimental investigation of the geometric structure of an opposing unexpanded jet. It discusses flow conditions with interaction between the jet and sub- and supersonic flows. It is shown that, with the outflow of an unexpanded jet counter to a supersonic flow, there are unstable flow conditions. For stable flow conditions with one roll, dependences are proposed determining the form of a jet in a supersonic opposing flow. A generalized dependence is obtained for the distribution of the pressure at the surface of a body with a jet, flowing out counter to a subsonic flow. The range of change in the determining parameters are the following: Mach numbers at outlet cross section of nozzle, M a = 1 and 3; Mach numbers of opposing flow, M∞ = 0.6−0.9 and 2.9; degree of effectiveness of jet, n = p a /p∞ = 0.5−800 (p a and p∞ are the static pressures at the outlet cross section of the nozzle and in the opposing flow); the ratios of the specific heat capacities, γ a = γ∞ = 1.4; the drag temperatures of the jet and the flow, To∞ = Toa = 290°K.