[A-OS16] Frontiers of Ocean Mixing Research

[AOS16-01] Internal Solitary Waves with Cores

*Kevin G Lamb¹ (1.University of Waterloo)

キーワード：Internal Solitary Waves, core, mixing, wave-wave interaction

Under appropriate background conditions internal solitary waves may have surface or subsurface cores. Solutions of the Dubreil-Jacotin-Long equation predict cores with closed isopycnals and, in a reference frame moving with the wave, closed streamlines. In numerical simulations of a time-evolving field these cores are usteady and leaky: fluid is continually being entrained into the core where it is mixed before leaking out of the rear of the core. In this talk I will present an overview of ISWs with cores, the conditions under which surface or subsurface cores may exist and recent results of numerical simulations of the interaction of two internal solitary waves, one with a core over-taking a smaller wave without a core. In general, during the interaction the large ISW decrease in amplitude while transferring energy to the smaller ISW. During this process the large ISW loses its core and the fluid inside the core is left behind. The smaller wave grows in amplitude and forms a new core. In many cases the final small ISW is considerably smaller than the initial small ISW while the larger ISW may be larger than the iniitial ISW. ISW energy is also lost to small amplitude internal waves.