Experimental characterization of the transition region in a rotating-disk boundary layer

A series of experiments were performed to study the transition from laminar to turbulent flow for the boundary layer over a rotating disk and to compare with theoretical results. The mean flow profile measured in the laminar region is found to be in excellent agreement with analytical results, and the spatial growth of natural disturbances matches linear theory predictions. A hot-wire sensor was positioned at different spatial locations to determine the evolution of natural disturbances. Spectral analysis at high resolution and ensemble-averages of velocity time series have been carried out to distinguish different flow regimes.