Penetration and mixing of multiple gas jets subjected to a cross flow

An experimental study of the interaction of a high-velocity airstream with jets from single row, multihole wall injectors is presented. Results are reported for tests conducted at nominal airstream Mach numbers of 0.6, 2, and 3. Injectant fluids included helium, argon, and Freon-12. One supersonic and twelve sonic wall injectors having various hole spacings, hole diameters, and injection angles were employed in these tests. The influence of a disturbed approach flow boundary layer on jet penetration and mixing was determined in tests with blowing upstream of the injector. Schlieren photographs of the injectant flowfield were taken and Pitot pressure, total temperature, and species concentration profiles were obtained at several tunnel locations. These data were employed to develop correlations for the penetration height, the distance required to achieve two-dimensional flow, and the kinematic eddy viscosity. The latter correlation establishes a connection between downstream mixing and initial jet penetration. It was found that small amounts of blowing upstream of the injectors significantly increases jet penetration and the rate of subsequent jet-airstream mixing.