The transient response of an elastic cylinder to a laser impact is studied. When the laser source is a line perpendicular to the cylinder axis, modes guided along the cylinder are generated. For a millimetric steel cylinder up to ten narrow resonances can be locally detected by a laser interferometer below 8 MHz. These resonances correspond to Zero-Group Velocity guided modes or to circumferent...

The physical nature of the initial transition to three-dimensionality of #ow past a circular cylinder has been the subject of considerable debate in the literature. Of several proposed mechanisms, the possibility of classi"cation as an elliptical instability is re-examined in this article. Detailed Floquet analysis of the transition shows clear evidence of the growth of an elliptic instability ...

The fully nonlinear regular and focused wave propagation and diffraction around a vertical circular cylinder in a numerical wave tank are investigated. The Mixed Eulerian-Lagrangian approach is used to update the moving boundary surfaces in a Lagrangian scheme, in which a higher-order boundary element method is applied to solve the wave field based on an Eulerian description at each time step. ...

We report some experiments undertaken to investigate the origin of ordered and chaotic laminar vortex streets behind circular cylinders at low Reynolds numbers. We made simultaneous measurements of near wake longitudinal velocity and cylinder lateral vibration amplitude spectra for cylinder Reynolds numbers in the range from 40 to 160. For a non-vibrating cylinder the velocity energy spectra co...

Impedance matrices are obtained for radially inhomogeneous structures using the Stroh-like system of six first-order differential equations for the time-harmonic displacement-traction 6-vector. Particular attention is paid to the newly identified solid-cylinder impedance matrix Z(r) appropriate to cylinders with material at r = 0, and its limiting value at that point, the solid-cylinder impedan...

A numerical simulation of steady and unsteady two-dimensional flows past cylinder with dimples based on highly accurate pseudospectral method is the subject of the present paper. The vorticity and streamfunction formulation of two-dimensional incompressible NavierStokes equations with no-slip boundary conditions is used. The system is formulated on a unit disk using curvilinear body fitted coor...

This paper theoretically describes and experimentally verifies two mechanisms leading to longitudinal dispersion of a passive tracer in a random array of circular cylinders. We focus on moderate Reynolds numbers of order 10–1000, specifically the range characterized by unsteady cylinder wakes. In this regime, two mechanisms contribute to dispersion, each associated with a distinct region of the...

A narrow strip has been introduced as a control element to suppress vortex shedding from a cylinder. The strip is set parallel to the cylinder axis, and the key parameter of control in this study is the strip position, which is determined by the angle of attack of the strip and the distance between the strip and the cylinder axis. A circular cylinder and a square cylinder were tested respective...