A Spectral Filtering Procedure for Eddy-Resolving Simulations with a Spectral Element Ocean Model

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• 作者：Levin ; Julia G. ; Iskandarani ; Mohamed ; Haidvogel ; Dale B.
• 刊名：Journal of Computational Physics
• 出版年：1997
• 出版时间：October, 1997
• 年：1997
• 卷：137
• 期：1
• 页码：130-154
• 全文大小：853 K

文摘

The numerical simulation of turbulent oceanic flows is susceptible to the appearance of instabilities associated with the misrepresentation of nonlinear interactions among small-scale motions. Specialized filters and differencing schemes have been successfully used in the past to suppress the growth of these instabilities in finite-difference ocean models. Here, we introduce a new filtering procedure designed to control the growth of nonlinear instabilities in the spectral element solution of nonlinear oceanic flows. The new procedure involves two separate steps. First, a spectral filter is applied to the vorticity and divergence fields to damp oscillations in high-gradient regions and to restore spectral accuracy away from them. Second, the associated velocity field is computed from a set of Poisson equations, and its boundary conditions and interelement continuity are restored. This two-step strategy avoids the loss ofC⁰continuity and the weakening of Dirichlet boundary conditions that can result when the filter is directly applied to the velocity field.