Structure Dynamics, Vortex Dynamics and Fluid Loading on Structures in Waves and Currents

摘要

The long-term goals of the research have been to investigate the important mechanisms involved in the interaction of current and waves with structures in the ocean. In our studies of tethered spheres or hydro elastic cylinders in a current, we find that they can vibrate with a large amplitude in several different modes of vibration. By employing an analogy to airplane trailing vortices for the sphere VIV, we have been able to predict both the induced force, and the energy transfer responsible for the modes. The cylinder VIV modes are similar to those for bodies with two degrees of freedom, as well as for flexible cantilevers and pivoted cylinders. Perhaps the most significant discovery in this work, is the fact that resonance can extend to infinite flow velocities, if the mass of the structure falls below a special critical value. Our work has formed the basis of comprehensive papers in Journal of Fluid Mechanics and several other journals, and has led to an invited review of VIV in Annual Review of Fluid Mechanics. The P.I. has founded and chaired a series of international conferences on Bluff Body Wakes and Vortex-Induced Vibrations (USA IN 1998, France in 2000, Australia in 2002).