Visualisation on supersonic flow over backward-facing step with or without roughness
At Mach number 3.4, visualisation experiments of flowover backward-facing step (BFS) with or without roughness band attached on upstream wall are carried out via traditional schlieren and newly developed nano-tracer-based planar laser scattering (NPLS). The time-averaged flow characteristic of the reattachment region and the instantaneous rich structures of the redeveloping boundary layer in the s