Bulletin of the American Physical Society
71st Annual Meeting of the APS Division of Fluid Dynamics
Volume 63, Number 13
Sunday–Tuesday, November 18–20, 2018; Atlanta, Georgia
Session Q35: Geophysical Fluid Dynamics: Oceanographic II
12:50 PM–3:26 PM,
Tuesday, November 20, 2018
Georgia World Congress Center Room: B407
Chair: Subhas Venayagamoorthy, Colorado State University
Abstract ID: BAPS.2018.DFD.Q35.8
Abstract: Q35.00008 : Non-hydrostatic effects in supercritical oceanic lee waves*
2:21 PM–2:34 PM
Eric T Mayer
Eric T Mayer
Oliver B Fringer
Lee waves are characterized by the dimensionless numbers J=Nh/U and ε=Uk/N, where U and N are the background velocity and buoyancy frequency, and h and k are height and width scales of the bathymetry. For periodic bathymetry of supercritical height (J>O(1)), the lowest layers of the flow become blocked, and the wave drag saturates, allowing for simple parameterization. However, saturation based parameterization considers only one of the two dimensionless numbers.
To diagnose the role of ε in supercritical lee waves, we use idealized numerical simulations of oceanic scale lee waves and study the evolution of the lowest over-topping streamline. We find that after the onset of blocking, the lowest streamline exhibits bounces with horizontal scales of the internal gravity wavelength. To the background flow, these undulations represent ε=1 width bathymetry, which does not cause drag. Blocking thus has an additional non-hydrostatic effect which further reduces lee wave drag.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2018.DFD.Q35.8
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