2017/02/28 by Thierry Dauxois, Sylvain Joubaud, Philippe Odier +1 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Buoyancy #Classical mechanics #Context (archaeology) #Geology #Geophysics #Gravitational wave #Gravity current #Gravity wave #Instability #Internal wave #Ionosphere and magnetosphere dynamics #Mechanics #Ocean Waves and Remote Sensing #Oceanographic and Atmospheric Processes #Physics #nlin.PS #physics.flu-dyn
paper · pdf · doi:10.1146/annurev-fluid-122316-044539
published as Annual Review of Fluid Mechanics 50, 131-156 (2018)
arxiv created 2017/03/02 · openalex publication_date 2017/09/21 · arxiv updated 2021/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Internal gravity waves play a primary role in geophysical fluids: They contribute significantly to mixing in the ocean, and they redistribute energy and momentum in the middle atmosphere. Until recently, most studies were focused on plane wave solutions. However, these solutions are not a satisfactory description of most geophysical manifestations of internal gravity waves, and it is now recognized that internal wave beams with a confined profile are ubiquitous in the geophysical context. We discuss the reason for the ubiquity of wave beams in stratified fluids, which is related to the fact that they are solutions of the nonlinear governing equations. We focus more specifically on situations with a constant buoyancy frequency. Moreover, in light of recent experimental and analytical studies of internal gravity beams, it is timely to discuss the two main mechanisms of instability for those beams: (a) the triadic resonant instability generating two secondary wave beams and (b) the streaming instability corresponding to the spontaneous generation of a mean flow.