Large-Scale Unsteadiness in a Separation Bubble

Abstract

Large-scale unsteadiness in a separation bubble formed at the leading edge of a blunt flat plate with right-angled corners was studied experimentally. The relations between the low-frequency oscillation and accompanying wall-pressure fluctuations were clarified by means of conditional-sampling technique and cross-correlation measurements. A simple velocity-fluctuation model which includes the low-frequency fluctuation was presented to interpret the motion of instantaneous reattachment points in reattaching zone. Outcomes of the model were reasonably compared with the experimental results.