An efficient mode-splitting method for a curvilinear nearshore circulation model

Coastal Engineering
By: , and 

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Abstract

A mode-splitting method is applied to the quasi-3D nearshore circulation equations in generalized curvilinear coordinates. The gravity wave mode and the vorticity wave mode of the equations are derived using the two-step projection method. Using an implicit algorithm for the gravity mode and an explicit algorithm for the vorticity mode, we combine the two modes to derive a mixed difference–differential equation with respect to surface elevation. McKee et al.'s [McKee, S., Wall, D.P., and Wilson, S.K., 1996. An alternating direction implicit scheme for parabolic equations with mixed derivative and convective terms. J. Comput. Phys., 126, 64–76.] ADI scheme is then used to solve the parabolic-type equation in dealing with the mixed derivative and convective terms from the curvilinear coordinate transformation. Good convergence rates are found in two typical cases which represent respectively the motions dominated by the gravity mode and the vorticity mode. Time step limitations imposed by the vorticity convective Courant number in vorticity-mode-dominant cases are discussed. Model efficiency and accuracy are verified in model application to tidal current simulations in San Francisco Bight.
Publication type Article
Publication Subtype Journal Article
Title An efficient mode-splitting method for a curvilinear nearshore circulation model
Series title Coastal Engineering
DOI 10.1016/j.coastaleng.2007.05.009
Volume 54
Issue 11
Year Published 2007
Language English
Publisher Elsevier
Contributing office(s) Coastal and Marine Geology Program
Description 14 p.
First page 811
Last page 824
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