6 - Vortex-Induced Vibrations

Summary

Key concepts

Vortex-induced vibrations (VIVs) are part of the family of flow--structure interactions and thus of great practical importance in people's interactions with nature. They occur in many engineering situations, such as bridges, stacks, transmission lines, aircraft, offshore structures, thermo-wells, engines, heat exchangers, marine cables, flexible structures in petroleum production, and other hydrodynamic and hydroacoustic applications.

Numerous contributions to flow-induced vibrations (FIVs) in general and to VIVs in particular toward the understanding of the fundamental flow mechanisms and the acquisition of design data through insights into marine hydrodynamics, physical and numerical experiments, and theoretical analyses have collectively defined the objectives of the FIV and VIV research.

During the past century, a great deal of work has been done on flow-induced vibrations and fluid-elastic instability. The number of contributions has increased exponentially. Thus, the amount of time required for any one researcher to comprehend the literature and to plow through the empirical morass became an increasingly larger fraction of his research time. As one of the pioneers of our subject (G. V. Parkinson) stated (1974), “An elastic structure exposed to a fluid flow may vibrate under the action of flow for a variety of causes. If the incident flow is oscillatory, either in an organized form, as with the vortex street from an upstream body, or in the form of random turbulence, the structure will develop an oscillatory response. If the structure is streamlined, like an airfoil, and the incident flow is steady, the elastic characteristics in two or more degrees of freedom may permit the structure to extract energy from the flow so as to develop a catastrophic flutter.”