Swimming efficiencies of fish and cetaceans have been related to a certain synchrony between stroke cycle frequency, peak-to-peak tail/fluke amplitude and mean swimming speed. These kinematic parameters form a non-dimensional wake parameter, referred to as a Strouhal number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. Y...

an experimental study was carried out on the wake of a cylinder on the back of which a plate is installed parallel to the fluid flow, with different terminal angles, where the reynolds number is 50000. at the end of the plate, blades with the height of 0.25 equal to the cylinder diameter and with 45, 90 and 135 degrees angle from the horizon, are installed where the cylinder diameter is equal t...

A rationale for the empirically observed Strouhal-Reynolds number relation for vortex shedding in the wake of a cylinder is provided. This rationale derives from a mechanism of vortex formation observed in numerical simulations of two-dimensional vortex shedding coupled with an order of magnitude estimate of the terms in the vorticity transport equation based on this mechanism.

Experiments with circular cylinders in high-speed flow reveal new universal behavior associated coherent oscillations the near-wake region. The Strouhal number shows invariance respect to both Reynolds and Mach number. Further, disturbances top bottom halves of wake have an anti-symmetric relationship.

Abstract The wake past a smooth cylinder perpendicular to the flow is studied 15 D (cylinder diameters) downstream by using particle image velocimetry (PIV). Spatial shedding period used estimate spatial Strouhal number (Sh) and compare with time-resolved hot-wire anemometer (HWA). vortices are detected within fluctuation field. statistical vortex properties do not change explored range of Reyn...