2018/04/20 by G. Pillet, E. V. Ermanyuk, L. R. M. Maas +2
Computer Science · Earth and Planetary Sciences · Physics and Astronomy · #Attractor #Internal wave #Nonlinear Dynamics and Pattern Formation #Nonlinear Photonic Systems #Oblique case #Oceanographic and Atmospheric Processes #Perpendicular #Ray tracing (physics) #Reflection (computer programming) #Refraction #Total internal reflection #Transverse plane #Transverse wave #physics.flu-dyn
paper · pdf · doi:10.1017/jfm.2018.236
published as Journal of Fluid Mechanics 845, 203-225 (2018)
openalex publication_date 2018/04/20 · arxiv created 2018/05/11 · openalex created_date 2018/05/17 · arxiv updated 2021/02/10 · openalex updated_date 2026/08/05
We study experimentally the propagation of internal waves in two different three-dimensional (3D) geometries, with a special emphasis on the refractive focusing due to the 3D reflection of obliquely incident internal waves on a slope. Both studies are initiated by ray tracing calculations to determine the appropriate experimental parameters. First, we consider a 3D geometry, the classical set-up to get simple, two-dimensional (2D) parallelogram-shaped attractors in which waves are forced in a direction perpendicular to a sloping bottom. Here, however, the forcing is of reduced extent in the along-slope, transverse direction. We show how the refractive focusing mechanism explains the formation of attractors over the whole width of the tank, even away from the forcing region. Direct numerical simulations confirm the dynamics, emphasize the role of boundary conditions and reveal the phase shifting in the transverse direction. Second, we consider a long and narrow tank having an inclined bottom, to simply reproduce a canal. In this case, the energy is injected in a direction parallel to the slope. Interestingly, the wave energy ends up forming 2D internal wave attractors in planes that are transverse to the initial propagation direction. This focusing mechanism prevents indefinite transmission of most of the internal wave energy along the canal.