SSeCoID fellow Himpu Marbona has made significant progress in understanding airflow separation over wall-mounted bumps, a phenomenon similar to what occurs on low-pressure turbine blade suction sides. His study, «Impact of Harmonic Inflow Variations on the Size and Dynamics of the Separated Flow over a Bump,» recently published in Physical Review Fluids, reveals distinct patterns in separated airflow behavior.
The research identified three key scenarios:
Scenario 1: Dominated by periodic ejection of Kelvin-Helmholtz instabilities, typically occurring under steady inflow or low-frequency, low-amplitude fluctuations.
Scenario 3: Characterized by instabilities pushed downstream as vortex clusters, usually resulting from high-frequency, high-amplitude fluctuations. This scenario leads to a significant reduction in separation length.
Interestingly, the study also uncovered instances where Scenarios 1 and 3 occur simultaneously.
Moving forward, Marbona plans to investigate these scenarios further under both laminar and turbulent conditions, aiming to develop improved methods for controlling airflow separation. This research could have significant implications for enhancing the efficiency of low-pressure turbines in gas turbine engines.
