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...

In this work, we focus on two-dimensional, incompressible viscous channel flow over an infinitely long cylinder and examine the effect of controlled rotational cylinder oscillation in reducing the drag exerted on the cylinder. Based on an analysis of the open-loop simulations, a control system is designed that automatically determines the frequency of cylinder oscillation, based on the Reynolds...

Experiments are conducted in a shock tube to study the shock loading of a cylinder and a cylinder bank. The experiments model the loading of the cooling tubes in an inertial confinement fusion reactor where banks of tubes line the reaction chamber. The diffraction of the shock wave is visualized using shadowgraphy. Shock loading of the cylinder(s) is measured with flush mounted piezoelectric pr...

We present an experimental study of the motion of a viscoelastic micellar fluid around a moving cylinder, which ranges from fluidlike flow to solidlike tearing and fracture, depending on the cylinder radius and velocity. The observation of crack propagation driven by the cylinder indicates an extremely low tear strength, approximately equal to the steady state surface tension of the fluid. At t...