| Development of rapid maneuvering control algorithms for Army supersonic missiles at low altitudes using low blowing ratio reaction jets is complicated by nonlinear, counterintuitive surface interactions, hot gas effects and poor predictability using modern computation fluid dynamic codes, where turbulence modeling is a key factor limiting the accuracy. The objectives of this research, which were directly tied to the Army low blowing ratio reaction control jet requirements, were documentation and improved understanding of (1) the surface flow interactions with hot gas effects and (2) the turbulent flow structure in the plume. An experimental analysis of the mean and turbulent flow properties for sonic and Mach 3 injection into a Mach 3 freestream was accomplished. The range of conditions included: MPR = 0.005–0.09, pj/p∞ = 0.6–19.0, Tj/T∞ = 1.0–13.6 (helium was used to simulate the highest temperature), γ = 1.4 and 1.67, and peb/p∞ = 0.19–6.15 (overexpanded, perfectly expanded and underexpanded jets were tested). Numerical simulations were not accomplished in the present effort. However, a full characterization of the high-speed jet interaction flowfield over a blended body missile fuselage (sharp-coned cylinder) was experimentally achieved, where specific pragmatic and scientific flowfield conclusions were drawn. The present data suggest a strong qualitative correlation between the measured shear strain rate field and the turbulence across the plume, which supports the usage of the Boussinesq turbulence model approximation. |
