Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Rodney D. W. Bowersox, PhD


In pursuit of more efficient and effective fuel-air mixing for a SCRAMJET combustor, this study was conducted to investigate relative near field enhancements of penetration and mixing of a discrete low-angled (25°) injected air jet into a supersonic (M=2.9) cross flow. The enhancements were achieved by injecting the transverse air jet parallel to the compression face of eight different ramp geometries. The jet-ramp interactions created collinear shock structures, baroclinic torque vorticity enhancement, ramp spillage enhanced vorticity, magnus effect penetration enhancement, and increased total pressure loss. Shadowgraph photography was used to identify the shock structures and interactions in the flow field. Measurements of mean flow properties were used to establish the jet plume size, jet plume penetration and to quantify the total pressure loss created by the ramps. Rayleigh-Mie scattering images were used for both qualitative flow field assessments and quantitative analysis of the plume trajectory and mixing rate. Results indicate that up to a 20% increase in penetration height and plume expansion can be achieved by injection over a ramp compared to simple transverse injection. This increase in penetration and mixing incurs up to a 15% loss in total pressure. The most critical geometric aspects that affect the flow are the ramp compression face shape and frontal aspect, and the location and strength of ramp generated expansion.

AFIT Designator


DTIC Accession Number



The DTIC-sourced PDF of this thesis has some portions illegible.