EFFECTS OF FREE-END CONDITION ON END-CELL-INDUCED VIBRATION

✍ Scribed by T. KITAGAWA; Y. FUJINO; K. KIMURA

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 349 KB
• Volume: 13
• Category: Article
• ISSN: 0889-9746
• DOI: 10.1006/jfls.1999.0214

✦ Synopsis

Wind tunnel experiments were conducted to investigate the characteristics of the transversewind vibration of a pivoted circular cylinder. It is con"rmed that a vibration, which is similar to the vortex-induced vibration, occurs at a wind speed higher than the threshold wind speed for the vortex-induced vibration. Special attention is paid to the cause of that vibration. In this study, that vibration is called as &&end-cell-induced vibration (ECIV)'', and the mechanism of ECIV is investigated. The measurement of the wind velocity #uctuation behind the model at various heights indicates that vortices whose frequency is much lower than the Karman vortex shedding frequency are generated around the free end of the model. This vortex is called &&tip-associated vortex'' in this study. ECIV occurred at the wind speed where the frequency of these vortices coincides with the natural frequency of the model. Therefore, ECIV is thought to be caused by tip-associated vortex shedding. Furthermore, based on the conjecture which the three-dimensional #ow around the free-end a!ects the generation of the tip-associated vortices, a thin circular disk is attached to the model top and its diameter is varied. The e!ects of the circular disk on ECIV and on the generation of the tip-associated vortices are studied experimentally.