We examine a two-dimensional deep-water surface gravity wave packet generated by a pressure disturbance in the Lagrangian reference frame. The pressure disturbance has the form of a narrow-banded weakly nonlinear deep-water wave packet. During forcing, the vorticity equation implies that the momentum resides entirely in the near-surface Lagrangian-mean flow, which in this context is often called the ``Stokes drift''. After the forcing turns off, the wave packet propagates away from the forcing region, carrying with it most of the energy imparted by the forcing. These waves together with their induced long wave response have no momentum in a depth integrated sense, in agreement with the classical results of Longuet-Higgins and Stewart (1962) and McIntyre (1981). The total flow associated with the propagating packet has no net momentum, in agreement with the classical results. In contrast with the finite-depth scenario discussed by McIntyre (1981), however, momentum imparted to the fluid during forcing resides in a dipolar structure that persists in the forcing region -- rather than being carried away by shallow water waves. We conclude by examining waves propagating from deep to shallow water and show that wave packets, which initially have no momentum, may have non-zero momentum in finite-depth water through reflected and trapped long waves. This explains how deep water waves acquire momentum as they approach shore. The artificial form of the parameterized forcing from the wind facilitates the thought experiments considered in this paper, as opposed to striving to model more realistic wind forcing scenarios.
Forced three-wave interactions of capillary-gravity surface waves
三波共振相互作用构成耦合毛细表面波的基本非线性机制。在之前的工作中，Haudin等人[Phys. Rev E 93，043110（2016）]，我们已经通过实验表征了这种子波机制的产生，其振幅由于粘性耗散而饱和。在这里，我们通过实验证明子波的产生验证了共振条件，但不是色散关系。通过模拟最低非线性阶的自由表面的响应，我们解释了这种观察作为一个强迫相互作用。{The自由表面的线性传递函数的带宽确实由于显著的粘性耗散而增加。这样就有可能观测到不遵循线性色散关系的自由表面激励。这种强迫三波相互作用机制可能会对实验或自然系统中具有不可忽略耗散的波湍流产生重要影响。
Gravity Wave Interactions in the Stratocumulus-Topped Boundary Layer
Center for Turbulence Research, Stanford University（斯坦福大学湍流研究中心）；School of the Atmospheric Sciences, Nanjing University（南京大学大气科学学院）；Department of Physics, University of Toronto（多伦多大学物理系）
Nonlinear interaction between dynamo-generated magnetic fields, mean flows and internal gravity waves in stellar stably-stratified layers: From 3D to 1D
Laboratoire de Physique de l’Ecole normale superieure ENS Universite PSL CNRS Sorbonne Universite Universite de Paris（巴黎高等师范学院物理实验室）；Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) Northwestern University（西北大学天体物理学跨学科探索与研究中心）；Laboratoire d’Instrumentation et de Recherche en Astrophysique (LIRA) Observatoire de Paris Université PSL Sorbonne Université Université Paris Cité CY Cergy Paris Université CNRS（巴黎天文台天体物理仪器与研究实验室）；Université Paris-Saclay CNRS Institut d’astrophysique spatiale（巴黎萨克雷大学空间天体物理研究所）；Departament d’Astronomia i Astrofisica Universitat de Valencia（瓦伦西亚大学天文学与天体物理学系）；Institut Universitaire de France (IUF)（法国高等研究院）
Observation of Phase Space Dynamics of Inverted Harmonic Oscillator
School of Electrical and Computer Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University（特拉维夫大学弗莱什曼工程学院电气与计算机工程系）；Department of Mathematics, Massachusetts Institute of Technology（麻省理工学院数学系）；German Aerospace Center (DLR), Institute of Quantum Technologies（德国航空航天中心量子技术研究所）；School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University（特拉维夫大学工学院机械工程系）
