1. Direct numerical simulation of laminar turbulent transition
2. Stability theory of shear flows (LST, PSE, Adjoint equations, Global instability).
3. Receptivity of boundary layer to external perturbations.
J. Ren, S. Fu, A. Hanifi “Stabilization of the hypersonic boundary layer by finite-amplitude streaks” Physics of Fluids, 28(2) (2016)024110.
J. Ren, S. Fu “Secondary instabilities of Görtler vortices in high-speed boundary layer flows” Journal of Fluid Mechanics, 781 (2015)388-421.
J. Ren, S. Fu “Study of the discrete spectrum in a Mach 4.5 Görtler flow” Flow, Turbulence and Combustion, 94(2) (2015)339-357.