Vortex shedding from spheres at Reynolds numbers from 3Y.10 to 4Y.10 in a uniform flow was investigated experimentally. Standard hot-wire technique were used to measure the vortex shedding frequency from spheres in a low-speed wind tunnel. Flow-visualization experiments were carried out in a water channel. Important results from the investigation were that (i) the variation of the Strouhal numb...

The behaviour of the wake Strouhal number for flow past a cylinder close to a free surface at both low and moderate Froude numbers is investigated numerically. For the low Froude number case (i.e., gravity-dominated), the results obtained are similar to those for flow past a cylinder close to an adjacent no-slip boundary. As the distance between the wall and the cylinder is reduced, the Strouha...

The aim of the paper is to present parameters new biomimetic folding fins measured using image processing. Tests were carried out for different types and compared most popular on market. A noninvasive processing method was used estimate divers’ velocities in vertical horizontal directions frequency amplitude fin trailing edge, as a result, Strouhal number calculated. These tests are continuatio...

Mach wave radiation in a turbulent fully expanded supersonic jet is revisited. Our goal is to determine the extent to which predictions for the radiated sound that are based on linearized analysis agree with solution of the full nonlinear equations. To this end, we solve the linearized Navier-Stokes equations (LNS) with precisely the same mean flow and inflow disturbances as a previous direct n...

The wake behind a circular cylinder in Mach 4 flow is examined experimentally in the Reynolds number range 2× 104 to 5× 105. Periodic oscillations of the sliplines in the wake are observed. The Strouhal number of the oscillations based on the diameter of the cylinder is found to increase monotonically from 0.30 to 0.50 with increasing Reynolds number. If the Strouhal number is formed using the ...

Particle Image Velocimetry (PIV) is used to investigate the three-dimensional wakes of rigid pitching panels with a trapezoidal geometry, chosen to model idealized fish caudal fins. Experiments are performed for Strouhal numbers from 0.17 to 0.56 for two different trailing edge pitching amplitudes. A Lagrangian Coherent Structure (LCS) analysis is employed to investigate the formation and evolu...

We noted in the main text the high Strouhal number corresponding to both our and Kern & Koumoutsakos (2006) optimal e cient swimmer's, and attributed this to the lower Reynolds number used in these computational works compared with the analyses in Triantafyllou et al. (1993); Taylor et al. (2003), consistent with Gazzola et al. (2014). However, both in Kern & Koumoutsakos (2006) and in the curr...