Vortex-Induced Vibration: Universal Phenomena in Diverse VIV Systems
Abstract
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. We have studied the ultra-high resolution controlled vibration of cylinders in a flow, and have been able to accurately predict free vibration response, as well as to understand free vibration phenomena, by employing "energy portrait" diagrams. We have constructed an accurate map of force and vortex modes in the plane of amplitude-wavelength, which relates well to the earlier Williamson-Roshko map of modes (1988). We discover new modes of vibration and vortex dynamics for a rising sphere, which are defined as the R, 2R and 4R modes, the latter comprising 4 vortex rings per cycle of its zig-zag trajectory. From a large set of very careful experiments involving rising and falling spheres, we have defined a new map of trajectories and vortex mode regimes, in the plane of mass ratio and Reynolds number. A significant discovery in this work, is the existence of a critical mass for unrestrained bodies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 28, 2011
- Accession Number
- ADA553774
Entities
People
- Charles H. Williamson
Organizations
- Sibley School of Mechanical and Aerospace Engineering