Study on flow-induced vibration characteristics of air-inflated shield sluice based on hydrodynamic model

Due to high efficiency and environmental friendliness, the air-inflated shield gate has been widely used in discharge structures in recent years. However, its flow-induced vibration characteristics are not yet fully understood. This paper takes the discharge sluice of the Tacheng project at the tail of the Fuhe River as a case study. First, the pulsating pressure and flow patterns of the air-inflated shield gate were investigated through a hydrodynamic physical model, and the results were used as input conditions for three-dimensional numerical simulation. Based on this, the natural vibration characteristics and vibration response of the air-inflated shield gate were analyzed. The results indicate that under various operating conditions, the maximum fluctuating pressure on the gate is 4.22×9.81 kPa, the standard deviation of fluctuating pressure is less than 0.1×9.81 kPa, and the dominant frequency is below 0.2 Hz. The natural frequency of the gate is above 3 Hz, indicating a low risk of vibration-induced damage. The vibration of the gate leaf is primarily in the direction perpendicular to the gate panel, with a maximum vibration displacement of 1.53×10-6 m and a maximum vibration acceleration of 2.88 ×10-3m/s2. The vibration response of the gate to fluctuating pressure is extremely weak, suggesting a low probability of hazardous conditions. Under small opening and high water head difference, the upper part of the gate′s back panel is subjected to dynamic water flow and reverse rotational flow. In practical applications, prolonged operation of the air-inflated shield gate under unfavorable flow conditions should be avoided. The research findings can provide references for the design and safe operation of similar air-inflated shield gates.