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An AMG strategy for efficient solution of free-surface flows

Andrew Gavin Bradford Mowat (Department of Mechanical Engineering, University of Cape Town, Cape Town, South Africa.)
Wilhelm Johann van den Bergh (Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria, South Africa.)
Arnaud George Malan (Department of Mechanical Engineering, University of Cape Town, Cape Town, South Africa.)
Daniel Wilke (Department of Mechanical & Aeronautical Engineering, University of Pretoria, Pretoria, South Africa.)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 3 May 2016

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Abstract

Purpose

An area of great interest in current computational fluid dynamics research is that of free-surface modelling (FSM). Semi-implicit pressure-based FSM flow solvers typically involve the solution of a pressure correction equation. The latter being computationally intensive, the purpose of this paper is to involve the implementation and enhancement of an algebraic multigrid (AMG) method for its solution.

Design/methodology/approach

All AMG components were implemented via object-oriented C++ in a manner which ensures linear computational scalability and matrix-free storage. The developed technology was evaluated in two- and three-dimensions via application to a dam-break test case.

Findings

AMG performance was assessed via comparison of CPU cost to that of several other competitive sparse solvers. The standard AMG implementation proved inferior to other methods in three-dimensions, while the developed Freeze version achieved significant speed-ups and proved to be superior throughout.

Originality/value

A so-called Freeze method was developed to address the computational overhead resulting from the dynamically changing coefficient matrix. The latter involves periodic AMG setup steps in a manner that results in a robust and efficient black-box solver.

Keywords

Acknowledgements

This work was supported by the South African Research (SARChI) Chair in Industrial CFD. SARChI is funded by the Department of Science and Technology (DST) and the National Research Foundation (NRF).

Citation

Mowat, A.G.B., van den Bergh, W.J., Malan, A.G. and Wilke, D. (2016), "An AMG strategy for efficient solution of free-surface flows", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 26 No. 3/4, pp. 1172-1186. https://doi.org/10.1108/HFF-09-2015-0389

Publisher

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Emerald Group Publishing Limited

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