A multiscale algorithm for simulating spatially-extended Langmuir circulation dynamics

Ziemowit Malecha

doi:10.1016/j.jcp.2013.07.003

2014-08-01

PRE

Ziemowit Malecha

Keith Julien

DOI：10.1016/j.jcp.2013.07.003

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摘要

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A multiscale algorithm is proposed for simulations of the spatially-extended dynamics of Langmuir circulation, a wind- and surface-wave-driven convective flow that dominates vertical transport and mixing on the scale of the 0 (100)-m deep ocean surface boundary layer. The algorithm is motivated by multiple scale asymptotic analysis of the master partial differential (Navier-Stokes-like) equations and comprises coupled equation sets for the fine- and coarse-scale dynamics. A primary virtue of the resulting multiscale formulation is that dynamical teleconnections between the fine and coarse scales are explicitly identified and computed, enabling fewer fine-scale domains than coarse-scale grid points to be used. Quantitative comparisons between the multiscale simulations and direct numerical simulations of the master partial differential equations are made. Good agreement is demonstrated in the appropriate parameter regime at a cost that is orders of magnitude less than that required for brute-force simulations using the single-scale algorithm. Several novel multiscale physical interactions are identified, highlighting the utility of the algorithm and the potential importance of spatiotemporal modulation of the convective flow on the mean dynamics. (C) 2013 Elsevier Inc. All rights reserved.

Keyword:

Multiple scale asymptotic analysis

Multiscale simulation

Ocean submesoscale

Langmuir circulation