A.O. Başkaya, S. Hickel (2025)
Physics of Fluids 37: 116108. doi: 10.1063/5.0281627
We present novel observations from direct numerical simulations of transitional Mach 8 flow over a 15° compression ramp ablator. Heating streaks over the ramp are seen to undergo a half-wavelength shift near the location of transition from laminar to turbulent boundary layer flow. This phenomenon leads to an intriguing pattern of ablation grooves on the surface. Our analysis shows that the underlying mechanism is driven by the baroclinic torque in the strongly stratified near-wall region. We discuss the impact of this baroclinic shift for a surface undergoing ablative recession and assess its sensitivity to different thermal boundary conditions and perturbation amplitudes.