Roughness-induced bypass transition, revisited

A study was conducted to determine inconsistencies in transition location and disturbance evolution of an array of cylindrical roughness elements. The spanwise arrays of cylindrical roughness elements were place in flat plate boundary-layer flow of the plate's edge. The study used the values of Reynolds number based on roughness height of an individual roughness element. The study found complete transition and fully turbulent flow about 100mm of the roughness elements. The study proved that the sensitivity of the disturbance energy to the Reynolds number was based on the boundary-layer scale and the dimensionless spanwise spacing of the roughness elements. The study also observed the transition location and the finer-scale structures in the streamwise velocity contours.