Effects of geometric parameters and arrangement of three-dimensional secondary recirculation jets on shock wave/turbulent boundary layer interaction in a supersonic isolator

Shock wave/turbulent boundary layer interaction (SWBLI) in supersonic internal flows can induce large-scale flow separation, strong pressure rise, and localized thermal loading, thereby degrading inlet performance and operability. Building on passive flow control concepts, this study numerically investigates a three-dimensional secondary recirculation jet (SRJ) as a control strategy for SWBLI in a supersonic isolator. Through steady simulations, the effects of key geometric parameters, the number of SRJ units, and their spanwise arrangement are systematically examined to clarify the mean-flow control behavior and identify more effective configurations. The results show that the SRJ suppresses the separated low-momentum region by extracting fluid from the separation bubble and re-injecting it into the near-wall flow, thereby modifying the time-averaged shock structure and promoting boundary layer recovery. Among the single-SRJ configurations, the best-performing case reduces the separation-bubble volume by 37.70% relative to the uncontrolled baseline. Increasing the number of SRJ units further enhances the control effectiveness, and the optimized five-unit arrangement yields a maximum reduction of 83.75% relative to the single-unit reference. The SRJ also significantly alters the three-dimensional skin-friction topology and weakens the broad high-pressure footprint associated with SWBLI. However, the modified near-wall topology may still concentrate wall heat transfer near separation and reattachment, with the dominant Stanton-number peak appearing downstream of reattachment. These results indicate that the SRJ is a promising passive method for mitigating SWBLI at the mean-flow level in supersonic isolators, although further unsteady investigations are still needed to assess its influence on intrinsic low-frequency dynamics and thermal-load evolution.