Abstract

A 1:25 scale physical model test was employed to study the plane gate vibration and holding force under the conditions of the fixed gate opening and closing process, respectively. We paid more attention to the characteristics of the gate vibration, holding force and the failure of gate-closing in closing process. The correlation between gate vibration and holding force was further examined. The results show that vertical vibration is weaker than the lateral and horizontal vibrations in fixed gate opening and is stronger than the lateral and vertical vibrations in closing process. Gate vertical vibration is self-excited vibration with a frequency of 7–14 Hz. Besides, crawl vibration in closing process is related to the upstream water depth. The higher the water level is, the earlier the crawl vibration appears. After the crawl stage, plane gate stops motion at a certain distance from the chamber floor and then the failure of gate-closing happens. Finally, gate vibration in three directions is significantly correlated with the holding force. In closing process, holding force has positive correlation with the vertical vibration and has negative correlation with the lateral and horizontal vibrations. In the crawl stage, the average of correlation coefficient in lateral, vertical and horizontal direction is −0.723, 0.733 and −0.664, respectively. Thus, the influence of gate vibration on holding force should be taken into consideration in determining the hoists capacity.

Highlights

  • Vibration problems in water conservancy projects caused by spillway is a common phenomenon

  • Based on the mechanism of flow-induced vibration, Naudascher [7] divided the gate vibration into three categories: (1) gate vibration induced by the instability of water flow; (2) gate vibration induced by flow instability and structure feedback mechanism; and (3) gate vibration caused by the induced force generated by structure motion

  • Further studies on the characteristics of vortex shedding in closing process and the method for evaluating the gate vibration effect on the holding force will be summarized in our subsequent study

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Summary

Introduction

Vibration problems in water conservancy projects (including dams, gates and plants) caused by spillway is a common phenomenon. Much work so far has focused on the static load monitoring, vibration displacement, structural stress and so on These achievements were largely obtained by fixed gate opening, and the flow under the gate can be viewed as a steady flow [20,21,22,23]. To determine the characteristics of gate vibration and holding force in closing process, we simultaneously measured the gate acceleration and holding force through the physical model test and examined the correlation between the two variables. Further studies on the characteristics of vortex shedding in closing process and the method for evaluating the gate vibration effect on the holding force will be summarized in our subsequent study.

Physical Model Test
Schematic
Characteristics of Vibration
Vibration in Fixed Gate Opening
Vibration in Closing Process
Comparison of Vibration in Two Operation Modes
Characteristics of Holding Force
Holding Force in Two Operation Modes
Crawl Vibration in Closing Process
Correlation and Holding
Correlation in Fixed Gate Opening
Correlation in Closing Process
Conclusions
Full Text
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