Math @ Duke

Publications [#246942] of JianGuo Liu
Papers Published
 Liu, JG; Wang, C, A fourth order numerical method for the primtive equations formulated in mean vorticity,
Communications in Computational Physics, vol. 4 no. 1
(July, 2008),
pp. 2655, ISSN 18152406
(last updated on 2019/06/16)
Abstract: A fourthorder finite difference method is proposed and studied for the primitive equations (PEs) of largescale atmospheric and oceanic flow based on mean vorticity formulation. Since the vertical average of the horizontal velocity field is divergencefree, we can introduce mean vorticity and mean stream function which are connected by a 2D Poisson equation. As a result, the PEs can be reformulated such that the prognostic equation for the horizontal velocity is replaced by evolutionary equations for the mean vorticity field and the vertical derivative of the horizontal velocity. The mean vorticity equation is approximated by a compact difference scheme due to the difficulty of the mean vorticity boundary condition, while fourthorder longstencil approximations are utilized to deal with transport type equations for computational convenience. The numerical values for the total velocity field (both horizontal and vertical) are statically determined by a discrete realization of a differential equation at each fixed horizontal point. The method is highly efficient and is capable of producing highly resolved solutions at a reasonable computational cost. The full fourthorder accuracy is checked by an example of the reformulated PEs with force terms. Additionally, numerical results of a largescale oceanic circulation are presented. © 2008 GlobalScience Press.


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