Please join us for the following AOS Seminar for Thursday, May 18 at 4:00 PM in Spiess Hall Room 330.
Speaker: Dr. Lev Ostrovsky, University of Colorado Boulder
Title: "Strongly nonlinear internal waves in the ocean: Propagation and interaction with turbulence"
Internal waves (IW) is one of the main factors defining the dynamics of oceanic waters. In the upper ocean and in the shelf areas, they often exist as nonlinear structures, such as solitary waves (solitons) and their groups (“solibores”). Moreover, internal solitons are arguably the most ubiquitous form of solitons observed in nature. Moreover, as the observations of the last decades have shown that in many cases, especially in the coastal areas, internal waves are not just nonlinear but strongly nonlinear so that their propagation velocity can significantly differ from that of linear waves. In this presentation we outline theoretical models regarding such waves, including our strongly nonlinear evolution equations, and compare their results with observational data.
Another important problem to be touched on is how the internal waves interact with small-scale turbulence in the ocean. First, evidently, an IW can attenuate due to turbulent viscosity and diffusion. Second, stronger IW can support and even amplify turbulence; this can be a cause for ubiquitous existence of turbulent “spots” in the ocean. In the theory we use both semi-empirical (Reynolds-averaged) models and direct numerical simulation: some results were compared with the data of laboratory experiments.