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Vortex-induced vibration (VIV) is an important source of fatigue damage of offshore oil exploration drilling, export, production risers, including steel catenary risers (SCRs) and tension leg platform (TLP) tendons or tethers. These slender structures experience both current flow and top-end vessel motions, which both give rise to the flow ...
This vibration is the cause for overhead power line wires humming in the wind, [1] and for the fluttering of automobile whip radio antennas at some speeds. Tall chimneys constructed of thin-walled steel tubes can be sufficiently flexible that, in air flow with a speed in the critical range, vortex shedding can drive the chimney into violent ...
The vorticity equation of fluid dynamics describes the evolution of the vorticity ω of a particle of a fluid as it moves with its flow; that is, the local rotation of the fluid (in terms of vector calculus this is the curl of the flow velocity). The governing equation is:
A tuned mass damper is a device consisting of a mass-spring system that is specifically designed and tuned to counteract the vibrations induced by vortex shedding. When a tuned mass damper is installed on a cylindrical structure, such as a tall chimney or mast, it helps to reduce the vibration amplitudes caused by vortex shedding.
The Scruton number (Sc) is an important parameter for vortex-induced vibration (excitation) of structures, vibrations caused by rain or wind, dry inclined cable galloping, and wake galloping, the unstable airflow that forms around bridge cables and other cylindrically-structured buildings. [1]
A vortex tube is the surface in the continuum formed by all vortex lines passing through a given (reducible) closed curve in the continuum. The 'strength' of a vortex tube (also called vortex flux ) [ 11 ] is the integral of the vorticity across a cross-section of the tube, and is the same everywhere along the tube (because vorticity has zero ...
The parameter is named after Vincenc Strouhal, a Czech physicist who experimented in 1878 with wires experiencing vortex shedding and singing in the wind. [1] [2] The Strouhal number is an integral part of the fundamentals of fluid mechanics. The Strouhal number is often given as =,
The strength of a vortex line is constant along its length. Helmholtz's second theorem A vortex line cannot end in a fluid; it must extend to the boundaries of the fluid or form a closed path. Helmholtz's third theorem A fluid element that is initially irrotational remains irrotational. Helmholtz's theorems apply to inviscid flows.