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Cable Fairing
A cable fairing is a structure attached to a towed cable designed to streamline the flow around the cable, primarily in marine environments. Cables are faired primarily for two reasons: (1) to reduce normal drag and thus achieve more depth for a given cable scope and speed; and (2) to eliminate cable vibration caused by vortex shedding In fluid dynamics, vortex shedding is an oscillating flow that takes place when a fluid such as air or water flows past a bluff (as opposed to streamlined) body at certain velocities, depending on the size and shape of the body. In this flow, v ..., commonly known as cable strum.R. D. Blevins, "Flow-Induced Vibration" (Second Edition). New York: Van Nostrand Reinhold, 1990, p. 91. Types of cable fairing There are several major types of cable fairing: *Hard fairing: essentially a streamlined teardrop-shaped shell clamped in sections over the cable;Patent 4,567,841 “Fairing assembly for towed underwater cables.” *Ribbon fairing: flexible r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vortex Shedding
In fluid dynamics, vortex shedding is an oscillating flow that takes place when a fluid such as air or water flows past a bluff (as opposed to streamlined) body at certain velocities, depending on the size and shape of the body. In this flow, vortices are created at the back of the body and detach periodically from either side of the body forming a Kármán vortex street. The fluid flow past the object creates alternating low-pressure vortices on the downstream side of the object. The object will tend to move toward the low-pressure zone. If the bluff structure is not mounted rigidly and the frequency of vortex shedding matches the resonance frequency of the structure, then the structure can begin to resonate, vibrating with harmonic oscillations driven by the energy of the flow. This vibration is the cause for overhead power line wires humming in the wind, and for the fluttering of automobile whip radio antennas at some speeds. Tall chimneys constructed of thin-walled steel t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
