Hypersonic Boundary-Layer Stability and Transition to Turbulence

Abstract Prediction and control of the hypersonic boundary-layer transition from a laminar to a turbulent state are vital to developing future hypersonic systems – capable of reaching at least Mach 5, or approximately 3,800 mph.

The boundary-layer transition significantly impacts aerodynamic heating, drag force, and engine performance of highly maneuverable hypersonic systems operating at varying altitudes.

A fully turbulent flow assumption results in an excessive thermal protection system (TPS) weight in the design process. The design tools available to engineers still utilize basic engineering correlations developed from surface measurements of transition locations on wind tunnel models. However, the uncertainty of the transition location can be up to 300%.

Successful prediction and control of boundary-layer transition depend on a fundamental understanding of the underlying physical mechanisms of the hypersonic flow environment.

Kursat Kara
Kursat Kara
Associate Professor, Mechanical and Aerospace Engineering

Kursat Kara is an Associate Professor of Mechanical and Aerospace Engineering at Oklahoma State University and principal investigator of the Kara Aerodynamics Research Laboratory. His research spans hypersonic boundary-layer physics, unsteady aerodynamics, and the emerging interface of quantum computing and fluid dynamics. A dedicated educator and mentor, he teaches core and advanced courses—including Fundamentals of Aerodynamics, Computational Fluid Dynamics, Boundary-Layer Theory and Transition, and Quantum Computing—and supervises graduate and undergraduate projects in high-fidelity simulation and data-driven modeling. His work has been funded by NASA, NSF, Oklahoma NASA-EPSCoR, NAVAIR, ANSYS, and IBM Quantum. In 2025, he received the CEAT Excellent Faculty Award and was nominated for both the 2024 Excellent Teacher Award and the 2025 Excellent Faculty Award by OSU’s School of Mechanical and Aerospace Engineering. Dr. Kara earned his Ph.D. from Old Dominion University with a dissertation on hypersonic boundary layer receptivity to acoustic disturbances. He began his career as a research engineer at New England Analytics (supporting Sikorsky Aircraft), then completed a post-doctoral appointment at Penn State in hot jet simulations for aeroacoustics. In 2010, he helped establish the Aerospace Engineering Department at Khalifa University—where he won the President’s Faculty Excellence Award for Outstanding Teaching in 2015—before joining OSU. An active member of AIAA and APS, he served on the AIAA Applied Aerodynamics Technical Committee (2012–2021) and chaired/co-chaired multiple AIAA conferences. He also sits on the editorial board of Nature Scientific Reports and guest-edits its Quantum Computing collection.