The present invention relates generally to use of flexible fairings to reduce vibration of structures induced by exposure thereof to flow of a fluid medium.
The use of flexible fairings in protective surrounding relation to structures such as pipes and cables exposed to a fluid medium under flow, is generally known in the art especially within submerged seawater environment as disclosed for example in U.S. Pat. No. 5,421,413 to Allen et al. Such flexible fairings provide good drag reduction as well to avoid possibly damaging and noisy vortex-induced vibrations in cables or pipes. It is therefore an important object of the present invention to provide an effective and less costly flexible fairing type of protection for pipes or the like, subject to the damaging effect of a fluid medium undergoing flow within submerged seawater environment for example.
In accordance with the present invention, a flexible fairing is expanded to and maintained in a streamline shaped configuration by dynamic pressure ported internally, such pressure being generated by fluid flow across the fairing. The fairing is accordingly constructed to establish by inflation a streamline shape extending cross-sectionally from its leading edge to a trailing edge in the direction of flow of the fluid medium. Such fairing is swively mounted adjacent its leading edge by bushings on a pipe or cable for rotational displacement thereon to a position wherein the streamline shape is made to extend in the direction of fluid flow by fluid forces acting on the fairing. Various means are utilized to enhance establishment of the streamline shape, such as stiffening rods and separately flexible baffles positioned within flexible shroud material of the fairing in spaced relation to each other.