Flow Field Characteristics of Oblique Shocks Generated Using Microjet Arrays

摘要

High-momentum steady 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, depending on the application, by adjusting the pressure ratio. Building upon the results of prior studies, flow field measurements using Particle Image Velocimetry were obtained. The velocity field clearly shows the effect of the microjet-generated oblique shocks on the flow field. Changes in the velocity field across the oblique shock and the expansion fan are also clearly seen from these results. The strength of the microjet-generated shocks was found to be constant along the length of the shock. Properties of microjet-generated shocks are compared with oblique shocks using a ramp and differences and similarities between the two are found. Flow properties due to multiple parallel and coalescing shocks were also investigated to better understand the behavior of such flow features introduced using fluidic micro-actuators.