基于混沌理论的平板闸门流激振动特性
Research on the Characteristics of Flow Induced Vibration of Bulkhead Gate Based on Chaotic Theory

鉴于闸门流激振动过程的复杂性，对水弹性模型试验中闸门在不同开度下的实测加速度响应数据进行了混沌特性分析。首先，对实测数据进行相空间重构，分别采用平均互信息法和平均伪最近邻域法计算最佳时间延迟和最佳嵌入维数；然后，基于嵌入参数计算关联维数D2和最大Lyapunov指数λ1，并对各计算参数的分布规律进行分析。研究表明：闸门侧向振动的复杂性相对其他振动方向更高，中间开度时的振动复杂性比大开度或小开度更显著；竖直向振动与顺流向振动中呈现出了较低维(D2=3.342～5.130)的混沌吸引子，表明较少的独立变量即可描述闸门竖直向及顺流向振动的规律；λ1随闸门开度的变化规律呈现“两边小中间大”的趋势，表明闸门在中间开度时的振动预测准确性较低。
Chaotic characteristics analyses are conducted in a hydroelastic model test to measure the acceleration response data when different gates open due to the complexity of flow-induced vibration. First, phase space reconstruction is carried out in the measured data using average mutual information and the averaged false nearest neighbor method to calculate the optimum time delay and optimal embedding dimension. Based on these embedding parameters, the correlation dimension D2 and the largest Lyapunov exponentλ1 are calculated for each group, and the distribution law of calculation parameters is analyzed. The results show that: the lateral gate vibration is more complex than other directions, while the gate vibration complexity is more remarkable in intermediate openings; lower dimension (D2 = 3.342 ~ 5.130) chaotic attractors are present in vertical gate vibration and flow vibration, which means the vibration law of the gate along the vertical direction and flow direction can be described by fewer independent variables; and finally, λ1 of each measuring point variation with gate opening presents the trend “both sides small and the middle large”, which indicates that the vibration forecast accuracy is lower in intermediate openings.