Quantitative interpretation of vortices from a cylinder oscillating in quiescent fluid

摘要: The instantaneous, quantitative patterns of vortices arising from sinusoidal oscillation a cylinder in quiescent fluid are experimentally characterized for the first time using high-image-density particle image velocimetry. near-wake does not indicate separated layer distributed vorticity leading to single, large-scale vortex. Rather, sufficiently high Reynolds number, sequence small-scale concentrations is formed. Agglomeration only fraction adjacent forms larger-scale Simultaneously, opposite sense formed along base (rear) cylinder. Streamline typically indicate, however, vortex; it has circulation smaller than total all that revealed by streamlines. These observations interpreted context effective resolution flow images.