Characteristics of flow regimes for single plates of rectangular cross-section

Abstract

Flow characteristics including velocity fluctuations, acoustic pressure fluctuations and surface pressures have been measured for single plates of rectangular cross section with various chordto-thickness ratios C and a range of high Reynolds numbers. The flow measurements were complemented with hydrogen-bubble flow visualisation. The results obtained lead to some modification of the flow regimes proposed in the past. Symmetrical modes of vortex shedding, previously observed for the shedding from a circular cylinder, were detected. Frequency components lower than the characteristic shedding frequency were also measured in the flow and acoustic spectra for one of the flow regimes. These components are believed to arise from different types of vortex-corner interaction reported previously for a shear layer impinging on a corner. Results of measurements of separation bubble length for longer plates indicate that for plates shorter than C ≈ 17 the length of the bubble is influenced by the presence of trailing edges.