Decomposition of incident and reflected higher harmonic waves using four wave gauges
Decomposition of incident and reflected higher harmonic waves using four wave gauges
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DOI：
10.1016/j.coastaleng.2004.04.004
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发表时间：
2004-08
影响因子：
4.4
通讯作者：
C. Lin;Ching-Jer Huang
中科院分区：
文献类型：
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作者：
C. Lin;Ching-Jer Huang
这项研究提出了一种新技术，使用四个或更多空间分离的探头来分离入射和反射的高次谐波。规则波的高次谐波中的自由模式和锁定模式都可以被隔离。使用傅里叶变换将复杂波分解为单独的频率分量。应用最小二乘法来最小化可能的信号噪声引起的误差，并获得求解与波幅相关的未知参数的方程。提供了防止计算中出现奇异性的探针间距条件。通过应用该方法解析任意选定振幅的人工波，验证了该方法的准确性。还测试了该方法对实验不可避免的噪声的敏感性。对数值波浪池中水下防波堤上游和下游的探头收集的自由表面高程数据进行分析，以证明该方法的适用性。结果与使用 Goda 和 Suzuki 的方法获得的结果进行了比较 [Goda, Y., Suzuki, Y., 1976。随机波实验中入射波和反射波的估计。过程。第 15 海岸工程师Conf.，ASCE，第 828–845 页] 和 Mansard 和 Funke [Mansard，E.P.D.，Funke，E.R.，1980。使用最小二乘法测量入射和反射光谱。过程。第 17 海岸工程师会议，ASCE，第 154–172 页]。比较表明，该方法给出的一次谐波入射波幅值和反射波幅值与其他两种方法完全相同。使用该方法可以确定高次谐波中的全模态，而其他两种方法中高次谐波被假定为自由波。
This study proposes a new technique to separate incident and reflected higher harmonic waves using four or more spatially separated probes. Both the free and locked modes in the higher harmonics of the regular waves can be isolated. The complex waves are decomposed into individual frequency components using the Fourier transform. The least squares method is applied to minimize the error caused by possible signal noise and to obtain the equations for solving the unknown parameters related to the wave amplitudes. Probe spacing condition for preventing singularity in the calculation is provided. The accuracy of this method is verified by applying it to resolve artificial waves with arbitrarily selected amplitudes. The sensitivity of this method to the noise inevitably associated with the experiments is also tested. The free surface elevation data collected from probes located upstream and downstream of a submerged breakwater in a numerical wave tank are analyzed to demonstrate the applicability of this method. The results are compared with those obtained using the methods of Goda and Suzuki [Goda, Y., Suzuki, Y., 1976. Estimation of incident and reflected waves in random wave experiments. Proc. 15th Costal Eng. Conf., ASCE, pp. 828–845] and Mansard and Funke [Mansard, E.P.D., Funke, E.R., 1980. The measurement of incident and reflected spectra using a least squares method. Proc. 17th Costal Eng. Conf., ASCE, pp. 154–172]. The comparison indicated that this method gives exactly the same first harmonic incident and reflected wave amplitudes as the other two methods. The full modes in the higher harmonics can be determined using this method, while the higher harmonics are presumed to be free waves in the other two methods.