Abstract This study provides a novel method for reconstructing real-time nonlinear wave forces on a large-scale circular cylinder by considering second-order wave effects. Potential theory is utilized for deriving the expression of wave forces with the measured data of wave elevation. Approximate expressions of quadratic transfer functions are built with undetermined coefficients, which are resolved by using the historical data of measured wave elevation. Two different algorithms, including fast Fourier transform (FFT) and recursive least squares (RLS), are adopted for real-time reconstruction. Hydrodynamic tests are conducted in the wave flume on a circular cylinder to examine the effectiveness of the nonlinear reconstruction method. Comparative results demonstrate that the accuracy of real-time reconstructed wave forces is significantly enhanced by the present method. The over-prediction errors at force crests and the under-prediction errors at force troughs have been reduced. Furthermore, comparative results show that the nonlinear method implemented by the FFT algorithm provides more accurate results, whereas the RLS algorithm is more time cost efficient.

中文翻译：

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考虑二阶波效应的随机波场中的实时非线性圆柱波力重建

摘要 本研究为考虑二阶波浪效应的大尺度圆柱体上的实时非线性波浪力重建提供了一种新方法。利用势理论，根据波浪高度的实测数据推导出波浪力的表达式。二次传递函数的近似表达式是用未定系数建立的，这些系数是通过使用测得的波浪高程的历史数据来解决的。两种不同的算法，包括快速傅立叶变换（FFT）和递归最小二乘法（RLS），被用于实时重建。在圆柱上的波浪槽中进行了水动力试验，以检验非线性重建方法的有效性。对比结果表明，本方法显着提高了实时重建波浪力的准确性。减少了力峰的高估误差和力谷的低估误差。此外，比较结果表明，由 FFT 算法实现的非线性方法提供了更准确的结果，而 RLS 算法的时间成本效率更高。