Adaptive vertical layering in TELEMAC-3D

Adaptive vertical layering in TELEMAC-3D.
Cawthorn, C.J.and Bourban, S. and Mead, C.T. and Wood, M. and Turnbull, M.S.
In: XVIIIth TELEMAC-MASCARET User Conference, 19-21 October 2011, Paris, France. (Submitted) (2011)

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Official URL:http://www.opentelemac.org/images/clubu/2011/Proceedings_TELEMAC-2011.pdf
Abstract:Many processes in environmental hydraulics exhibit sharp spatial gradients of some physical variable(s) in a small localised part of the overall water column. Examples of this include spreading of dense or buoyant plumes and thermal or saline stratification in reservoirs. In this paper, we demonstrate a robust adaptive mesh redistribution (AMR) method coded for TELEMAC-3D. The AMR method aims to capture these sharp gradients without requiring an excessive number of mesh layers or any prior knowledge of the flow structure. Rather than increasing the number of mesh planes in regions of sharp spatial gradients, the idea of mesh redistribution is to maintain a fixed number of planes that move in response to the local solution structure. The movement of the planes is governed by a diffusion equation; an approach that is discussed in Ref. [1]. This approach is similar to that used in the popular GETM software (Ref. [2]). Mesh plane elevations linked to gradients in tracer concentration only are discussed in this paper, although the extension to include velocity shear and/or bathymetry in the equations governing plane placement is expected to be straightforward. We present preliminary results demonstrating that the AMR method can adapt to relatively thin tracer plumes without the increased mesh resolution that would be required with some form of sigma mesh. Comparisons are drawn with an alternative approach in which plane elevations are specified by the user based on some a priori knowledge of the flow structure. The AMR method, which requires neither prior information about the flow nor user input, can be seen to give very similar results for the spreading of dense and buoyant plumes.
Item Type:Conference or Workshop Item (Paper)
Subjects:Maritime > General
Coasts > General
ID Code:936
Deposited On:28 May 2014 14:14
Last Modified:21 Jul 2017 09:55

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