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Colloquium - Sullivan

Planetary Boundary Layer Research Using Turbulence Simulation
Peter Sullivan
National Center for Atmospheric Research

The atmospheric and oceanic planetary boundary layers are the crucial glue that connects the overlying atmosphere with land surfaces, and is ultimately the source of air-sea coupling. The PBLs control the fluxes of momentum, heat, and diffusion of constituents. Motions in the PBL are however turbulent and thus cannot be predicted by analytic theories. Moreover, field campaigns designed to gather observations in the PBL are challenging because of the inherent unsteadiness of the atmosphere and a host of complicating features. Turbulence simulation, and in particular large-eddy simulation (LES) provides an alternative tool to investigate turbulent processes in the PBLs in an idealized setting. In this overview talk, the background behind LES will be introduced and the numerical methods used to solve the governing equations will be presented. Simulation results including statistics and flow visualization for some canonical PBL problems will be shown. In particular, entrainment events in the atmospheric PBL and the effects of ocean waves in the oceanic PBL will be discussed.

Peter Sullivan received degrees in Civil Engineering: BS in 1975 from Colorado State University, Mechanical Engineering: MSc. in 1977 from University of British Columbia (Vancouver, Canada), and in Civil Engineering: PhD in 1984 from Colorado State University. After his graduate study, he worked in the aerospace industry from 1985-1991 at the Boeing Company as a member of the aerodynamics research group. Currently, he is a project scientist at the National Center for Atmospheric Research (NCAR) in the mesoscale and microscale division.

Sullivan's current research areas are turbulent flow in the atmospheric and oceanic planetary boundary layers, including entrainment at stably stratified interfaces, air-sea interaction and surface-wave effects, Langmuir circulations in the ocean, subgrid-scale modeling, grid nesting in large-eddy simulations, and fluid-structure interaction. He is experienced working with and developing large industrial computational fluid dynamic codes for transonic flows with viscous-inviscid interaction, has performed full scale flight test measurements, has conducted low-speed turbulence measurements in wind tunnels, and for the last several years has developed a large-eddy simulation model of the planetary boundary layers. He has experience working on a variety of supercomputer architectures.

Refreshments will be served in ECOT 831 immediately following the talk.
Hosted by Clarence (Skip) Ellis.

Department of Computer Science
University of Colorado Boulder
Boulder, CO 80309-0430 USA
May 5, 2012 (14:13)