The HyperCASL algorithm: A new approach to the numerical simulation of geophysical flows

JOURNAL OF COMPUTATIONAL PHYSICS

卷:228

Article

Fontane, Jerome¹  Dritschel, David G.¹ 

[1] Univ St Andrews, Sch Math & Stat, St Andrews KY16 9SS, Fife, Scotland

关键词: Contour dynamics;    Vortex methods;    Contour advection;    Geophysical flows;   

DOI  :  10.1016/j.jcp.2009.05.025

来源: Elsevier

【 摘 要 】

We describe a major extension to the Contour-Advective Semi-Lagrangian (CASL) algorithm [D.G. Dritschel, M.H.P. Ambaum, A contour-advective semi-Lagrangian numerical algorithm for simulating fine-scale conservative dynamical fields, Quart. J. Roy. Meteorol. Soc. 123 (1997) 1097-1130; D.G. Dritschel, M.H.P. Ambaum, The diabatic contour advective semi-Lagrangian algorithm, Mon. Weather Rev. 134 (9) (2006) 2503-2514]. The extension, called 'HyperCASL' (HCASL), uses Lagrangian advection of material potential vorticity contours like CASL, but a Vortex-In-Cell (VIC) method for the treatment of diabatic forcing or damping. In this way, HyperCASL is fully Lagrangian regarding advection. A grid is used as in CASL to deal with 'inversion' (computing the velocity field from the potential vorticity field). First, the novel aspects of the algorithm are described including several improvements to the underlying CASL algorithm. All numerical parameters are chosen so as to minimise the computational cost while improving conservation properties. Finally, a thorough inter-code comparison is conducted using a two-dimensional inviscid unforced turbulence test-case. This enables us to point out the advantages of this new algorithm in terms of resolution, computational cost and numerical diffusion compared to other existing methods, namely CASL, VIC and Pseudo-Spectral (PS) methods. (C) 2009 Elsevier Inc. All rights reserved.

【 授权许可】

Free