Flow-induced vibration of long-span gates caused by shedding vortices. (1st report. vibration criteria, level of fluid excitation and added mass).

Abstract

Submerged long span gates which dam a wide river undergo violent streamwise vibrations caused by vortex shedding beneath the gate. This study presents flow-induced vibration characteristics which were obtained in a model gate test. From the measured vibration frequencies and damping ratios in air and water, respectively, the level of fluid excitation and the added mass for small amplitude gate vibrations were calculated and reduced to a dimensionless form, and thus the vibration onset criteria were obtained. In addition to the average value of the maximum amplitude of gate vibration, was measured. The results of these experiments, taken as a whole, suggest that the flow-induced vibration characteristics of the long-span gates are well predicted by the dimensionless parameters, such as the reduced gate opening height and the reduced velocity.