Flowfield Characteristics of Oblique Shocks Generated using Microjet Arrays

High momentum microjet arrays are used to generate single and/or multiple oblique shocks in a supersonic crossflow. The properties of these microjet generated shocks can be tailored to be parallel or coalescing, at variable supply pressures, depending on the application. Flowfield measurements using Particle Image Velocimetry were obtained for a range of test conditions. The velocity field obtained clearly shows the global effect of the microjet generated oblique shocks on the flowfield. The jump in the velocity field across the oblique shock and the extent of the influence of the shock and expansion fan are also clearly seen from the results. The microjet generated shocks were compared with a ramp shock and it was found that the properties of the two share some similarity. The strength of the microjet shocks was found to be constant along the length of the shock. The results obtained were compared to previous results obtained using Background Oriented Schlieren and shadowgraph techniques and were found to be consistent. The parallel and coalescing properties of the multiple microjet shocks were also investigated.