On the behavior of higher harmonics in the evolution of nonlinear water waves in the presence of abrupt depth transitions

Wu，Qian1,2; Feng，Xingya2,3; Dong，You1; Dias，Frederic4

2023-12-01

10.1063/5.0173173

Physics of Fluids   影响因子和分区

1070-6631

1089-7666

The presence of abrupt depth transitions might trigger strong nonlinear effects on propagating water waves near coastal regions. In this study, the dynamics of nonlinear monochromatic waves over a submerged step representing the abrupt depth transitions are investigated both experimentally and numerically. Within the framework of the free-surface Euler equations, a fully nonlinear potential flow model based on a conformal mapping method is established to investigate the higher harmonics. The numerical method has been well validated with experimental measurements. To analyze the wave nonlinearity at the transitions, the higher harmonics are extracted both in the spatial and time domains. It is shown that abrupt depth transitions enhance the higher harmonic amplitudes in the shallower regions on the step. The effects of the incident wave frequency and height are studied. It is found that the higher harmonics induced by the abrupt depth transitions become more significant with increasing wave steepness. An analysis of the evolution of the skewness and kurtosis demonstrates the high asymmetry of the surface elevation on the upstream junction. The asymmetry shows clear nonlinear effect from the higher harmonics.

EI ; SCI

英语

通讯

20235015195506

Conformal mapping ; Harmonic analysis ; Higher order statistics ; Nonlinear equations ; Numerical methods ; Time domain analysis

Seawater, Tides and Waves:471.4 ; Mathematics:921 ; Numerical Methods:921.6 ; Mathematical Statistics:922.2

PHYSICS

2-s2.0-85179130111

Scopus

1.Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong
2.Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
3.State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian,China
4.School of Mathematics and Statistics,University College Dublin,Dublin,D04V1W8,Ireland

Wu，Qian,Feng，Xingya,Dong，You,et al. On the behavior of higher harmonics in the evolution of nonlinear water waves in the presence of abrupt depth transitions[J]. Physics of Fluids,2023,35(12).

Wu，Qian,Feng，Xingya,Dong，You,&Dias，Frederic.(2023).On the behavior of higher harmonics in the evolution of nonlinear water waves in the presence of abrupt depth transitions.Physics of Fluids,35(12).

Wu，Qian,et al."On the behavior of higher harmonics in the evolution of nonlinear water waves in the presence of abrupt depth transitions".Physics of Fluids 35.12(2023).