TURBULENT-FLOW STRUCTURE CHARACTERIZATION OF ANGLED INJECTION INTO A SUPERSONIC CROSS-FLOW

An experimental analysis of the three-dimensional, turbulent, compress ible flow structure of a highly underexpanded Mach 1.8 jet injected at an angle of 25 deg into a Mach 2.9 freestream is described. The exper imental methods include cross-film anemometry, conventional mean-how p robes (pitot and cone-static pressure), schlieren photography, and sur face oil-flow visualization. The mean-how data consist of axial mass f lux, y-z plane mass flux vector, and total pressure contour plots. Tur bulence data include x, y, and z mass flux turbulence intensity compon ents, x-y and x-z Reynolds shear stresses, and anisotropy coefficients . Two relatively large recirculation cells were located just downstrea m of the injector. In addition, the vortex pair within the plume drama tically affected the overall mean and turbulent flow structure. The ax ial turbulence intensity had two peaks that were collocated with the v ortex pair. The transverse and spanwise intensities peaked on the righ t and left sides of the plume, respectively. The anisotropy contours a lso showed a strong dependence on the secondary motion of the two coun ter-rotating vortices. In particular, the z-y coefficient had a maximu m located within one vortex, and a minimum in the other.