Device for inhibiting vortex-induced vibration of underwater standpipe of fish-tail imitating cowling

Abstract

The invention discloses a device for inhibiting vortex-induced vibration of an underwater standpipe of a fish-tail imitating cowling, belonging to field of laying technology of ocean standpipe facilities. The device is used for installing the fish-tail imitating cowling which can change the direction along with the flowing direction of water flow on the underwater standpipe. The device comprises a rotary module, a cowling fixing pad, a cowling and a fish-tail flexible plate, wherein the cowling has a figure of round front part and sharp rear part, has smooth surface and is slightly like the shape of a drip. The arc part of the cowling is coaxial with the standpipe. The cowling is connected with a main pipe by the rotary module that can be assembled and disassembled conveniently so that the cowling can rotate freely around the standpipe. A small-density buoyancy material is added to the hollow part of the cowling. The fish-tail flexible plate is arranged at the tail of the cowling so as to reduce the forward flow angle of the cowling, therefore, a better effect of reducing resistance and inhibiting vortex-induced vibration is achieved. The device can effectively inhibit the vortex-induced vibration; therefore, the anti-fatigue strength of the underwater standpipe can be improved, so as to greatly reduce the engineering cost. Simultaneously the limit of certain vortex-induced vibration inhibiting devices on the forward flow direction can be overcome, therefore, the device has extremely high application values in the environments where the water flowing direction of oceans orrivers changes frequently.

Description

technical field [0001] The invention relates to a vortex-induced vibration suppression device for an underwater riser, in particular to a vortex-induced vibration suppression device for an underwater riser using a fishtail-like fairing, and belongs to the technical field of marine riser facilities laying. Background technique [0002] The increasing shortage of oil supply has made deep sea oil and gas exploitation highly valued by countries all over the world. There are many slender and cylindrical structures in the deep sea production system, such as drilling risers, oil production risers and suspension transfusion pipelines, etc., and their total cost exceeds 50% of the entire deep sea production system. When waves and ocean currents flow through these pipelines, at a certain flow rate, the wake of the pipeline will produce periodic vortex shedding. When the natural frequency of the pipeline is close to the frequency of vortex shedding, vortex induced resonance occurs, whi...

AI Technical Summary

Problems solved by technology

Therefore, the application of fixed fairings has great limitations for operating environments where the direction of water flow often changes, such as oceans and rivers.

The application number is 201010571612.8, and the patent titled "Vortex Induced Vibration Suppression Device of Underwater Riser Using Rotatable Fairing" uses the rotation of the fairing to achieve the effect of adapting the flow direction, and partially eliminates the effect of the fairing on suppressing vortex-induced vibration. The disadvantage of being sensitive to the flow direction, but due to the influence of the incoming flow angle α is not small enough, its effect of reducing the lift resistance and vortex-induced vibration of the underwater riser is limited

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