In this paper, we establish some quantity relationships between the dynamics of circular cylinder wakes and the rotation speed of the cylinder. It has been shown analytically that rotating the cylinder can regularize the flow behavior, and delay the transition from steady flow to turbulent flow. The work needed to overcome the drag exerted on the cylinder is provided.

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...

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...

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...

A quasi three-dimensional numerical model is developed to study vortex-induced vibration (VIV) of two tandem flexible circular cylinders. In this model, the whole cylinder is divided into many sections along its length. The hydrodynamics of each section are represented by the solution of the two-dimensional Navier-Stokes equations. The dynamic response of the flexible cylinder is predicted by t...

A boundary value problem for certain elliptic operators in the comple ment of an in nite cylinder is studied We prove that for these operators P D with some general zero boundary conditions if P D u has support inside a cylinder and decays exponentially in one direction of the cylinder then the solution u under a certain strong radiation condition at in nity must have support inside the cylinde...