A series of numerical simulations two-degree-of-freedom vortex-induced vibration two coupled cylinders with unequal diameters are performed at the Reynolds number 20,000. The effects incident angle, spacing ratio, and diameter ratio on VIV responses for investigated. It is shown that lock-in range large cylinder significantly widened maximum amplitude decreases as a result existence small cylin...

The effect of triple helical grooves on the suppression vortex-induced vibration (VIV) a circular cylinder was investigated experimentally in wind tunnel over Reynolds number range 1 × 104 < Re 4 104. It found that were effective suppressing VIV with peak amplitude reduction approximately 36%. In addition, lock-on region also reduced. To explore mechanism for VIV, experiments flow structures...

The flow passing a circular cylinder can trigger flow-induced vibrations such as the vortex-induced vibration. In this paper, authors investigated an active method to control wake flow. scheme was achieved by blowing through structured porous surface that manufactured 3D printing precisely. momentum changed various mass rates so it defined different values of non-dimensional coefficient C ? . e...

Aerodynamic vibrations inherently occur on a long-span-length bridge. The vibrations are roughly classified into vortex-excited vibration and self-excited vibration both are induced by separation flow from the leading edge of the structure. As aerodynamic vibrations frequently cause fatal damage to the structure, the suppression method of vibration has been studied for a long time. Two methods ...

Marine propellers display several forms of cavitation. Of these, propeller-tip vortex cavitation is one of the important factors in propeller design. The dynamic behaviour of the tip vortex is responsible for hull vibration and noise. Thus, cavitation in the vortices trailing from tips of propeller blades has been studied extensively. Under certain circumstances cavitating vortices have been ob...

We report the investigation of vortex emission by a vibrating wire in superfluid 3He-B at a pressure of 28 bar. We used two vibrating wires with 47 Hz and 183 Hz resonance frequencies as a generator and a detector of vortices. The onset velocity of vortex emission for the 183 Hz vibrating wire is higher than a pair-breaking velocity, indicating that pair breaking causes vortex generation. In co...

many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...

The flow around a tethered cylinder subjected to an incoming flow transverse to its main axis and confined in a channel is investigated by means of global stability analysis of the full coupled body–fluid problem. When the cylinder is strongly confined (ratio of cylinder diameter to cell height, D/H = 0.66) we retrieve the confinement-induced instability (CIV) discovered by Semin et al. (J. Flu...