11B.6
Vorticity dynamics in the PBL using a vector-vorticity LES model
Chin-Hoh Moeng, NCAR, Boulder, CO; and A. Arakawa, J. H. Jung, R. Rotunno, and P. P. Sullivan
The word "vorticity" is often used to define or describe turbulence
in literature. However most investigations of PBL turbulence focus
on momentum dynamics, partly because velocity is easier to measure
compared to vorticity and also because large-eddy and direct numerical
simulations typically use the momentum-pressure formulation.
In this work we pose the following questions: What are the
vorticity dynamics in the PBL and how does vorticity dynamics contribute to
turbulent transport? We use a new large-eddy simulation (LES) code
that is based on the vector-vorticity model developed by Jung and
Arakawa (2008) to investigate vorticity dynamics in the atmospheric
PBLs. The model solves vorticity equations instead of the usual
momentum equations; its output consists of all three components
of vorticity, as well as the velocity field. We use the model
to perform an LES of a convective PBL with mean shear and analyze
vortical structures that contribute to transport and
Reynolds stress in the PBL.
Jung, J.-H. and A. Arakawa, 2008: A three-dimensional anelastic model
based on the vorticity equation. Mon. Wea. Rev., 136, 276-294.
Session 11B, LARGE EDDY SIMULATIONS AND FUNDAMENTAL STUDIES—III
Wednesday, 11 June 2008, 1:30 PM-3:00 PM, Aula Magna Höger
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