The flow at the leading edge and in the interior of a rectangular porous obstruction is described through experiments and scaling. The porous obstruction consists of an emergent, rectangular array of cylinders in shallow flow, a configuration that mimics aquatic vegetation. The main features of the flow depend upon the non-dimensional canopy flow-blockage, which is a function of the obstruction...

Microscopic particle-image velocimetry (microPIV) measurements are made in the streamwise–wallnormal plane of a 536 lm capillary at Re = 4,500 to study the statistical and structural features of wall turbulence at the microscale. Single-point velocity statistics, including the mean velocity profile, the root-mean-square streamwise and wall-normal velocities, and the Reynolds shear stress profil...

We study the dispersion of wind-induced near-inertial oscillations (NIOs) in a fully turbulent baroclinicmesoscale eddy Ž eld characterizedby a continuouswavenumber spectrum. The in uence of the eddy Ž eld on the horizontal dispersion of the differentNIO modes is analyzed using a vertical normal mode expansion. Previous studies have identiŽ ed two dispersion regimes: trapping and strong disper...

The study on the flow behave inside of a ball valve is important for heavy crude oil transportation. Owe to the fast progress of the numerical technique, it becomes an effective way to observe the flows inside a valve and to analyze the flow structure of the oil-water core annular flow. In the present study, the simulation of the oil-water core annular flowing through the valve is conducted...

An axi-symmetric and swirling vortex sheet is investigated as the simplest ow in which there is non-trivial vortex stretching and as a possible setting for studying vortex cancellation and singularity formation. Rayleigh's criterion indicates linear stability of a single sheet but instability for other conngurations of sheets. Due to the simplicity of vortex sheet problems, the linear modes and...

Steady, inviscid, axisymmetric vortex ows past a sphere are obtained numerically as solutions of a partial di erential equation for the stream function. The solutions found include vortex rings, bounded vortices attached to the sphere and in nite vortex tubes. Four families of attached vortices are described: vortex wakes behind the sphere, spherically annular vortices surrounding the spherical...

In a shaken Bose-Einstein condensate, confined in a vibrating trap, there can appear different nonlinear coherent modes. Here we concentrate on two types of such coherent modes, vortex ring solitons and vortex rings. In a cylindrical trap, vortex ring solitons can be characterized as nonlinear Hermite-Laguerre modes, whose description can be done by means of optimized perturbation theory. The e...

BACKGROUND LV diastolic vortex formation has been suggested to critically contribute to efficient blood pumping function, while altered vortex formation has been associated with LV pathologies. Therefore, quantitative characterization of vortex flow might provide a novel objective tool for evaluating LV function. The objectives of this study were 1) assess feasibility of vortex flow analysis du...

The motion of two-dimensional inviscid, incompressible fluid with regions of constant vorticity is studied for three classes of geophysically motivated problem. First, equilibria consisting of point vortices located near a vorticity interface generated by a shear flow are found analytically in the linear (small-amplitude) limit and then numerically for the fully nonlinear problem. The equilibri...