In the present study, an experimental investigation was performed to characterize the vortex induced vibration (VIV) of a flexible cable in an oncoming shear flow. The VIV tests were conducted in a wind tunnel with a flexible cable model. It was found that, under different oncoming velocity profiles, the cable model behaved in single-mode and multi-mode VIVs. The displacement amplitudes of the ...

A known bifurcation scenario describing the development and interaction of Mode A and Mode B vortex shedding modes of a circular cylinder wake is extended to predict the Strouhal–Reynolds number profile over the three-dimensional transitions. The mode amplitudes are described by coupled Landau equations and, with frequency information being included by the addition of complex coefficients, the ...

Predictive capability of RANS and LES models to calculate incipient cavitation of water in a step nozzle is assessed. The RANS models namely, Realizable k-ɛ, SST k-ω and Reynolds Stress Model did not predict any cavitation, due to the limitation of RANS models to predict the low pressure vortex cores. LES WALE model was able to predict the cavitation by capturing the shear layer instability and...

Quantized vortices play a key role in superfluidity and superconductivity. We have observed the formation of highly ordered vortex lattices in a rotating Bose-condensed gas. These triangular lattices contained over 100 vortices with lifetimes of several seconds. Individual vortices persisted up to 40 seconds. The lattices could be generated over a wide range of rotation frequencies and trap geo...

Numerical simulations have been used to study the phenomenon of autorotation of a flat plate hinged about its center in a freestream. The focus of the paper is on examining the effect of Reynolds number and plate thickness ratio on vortex induced rotation. The numerical solver employed is based on a sharp interface, Cartesian grid method that allows us to simulate flow with moving boundaries on...

In this paper, the results of laboratory investigation about the flow behind the sphere in the range of 150<Re<300 , where very interesting physical phenomenon occurs, are presented. After a first stationary transition where the flow breaks the axisymmetry, very controlled experiments allow one to define a threshold for the second transition from stationary to unstable flow, which includes thre...

This study discusses hydrodynamic effects of horizontal spoilers fixed on submarine pipelines. Numerical calculations are conducted to investigate the influences of the spoiler on flow profile, vortex shedding frequency, drag coefficients and lift coefficients. The calculation results demonstrate that attached horizontal spoilers could change the wake flow and enhance the self-burial of the pip...

Streamlines, contour lines, vector plots, and volume slices (cutting planes) are commonly used for flow visualization. These techniques are sometimes referred to as instantaneous flow visualization techniques because calculations are based on an instant of the flow field in time. Although instantaneous flow visualization techniques are effective for depicting phenomena in steady flows, they som...

An axisymmetric vortex-sheet model is applied to simulate an experiment of Didden (1979) in which a moving piston forces fluid from a circular tube, leading to the formation of a vortex ring. Comparison between simulation and experiment indicates that the model captures the basic features of the ring formation process. The computed results support the experimental finding that the ring trajecto...