Title: Effect of RANS-based turbulence models on nonlinear wave generation in a two-phase numerical wave tank

Authors: Ahmed Elhanafi; Alan Fleming; Zhi Leong; Gregor Macfarlane

Addresses: National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, Launceston, Tasmania 7250, Australia ' National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, Launceston, Tasmania 7250, Australia ' National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, Launceston, Tasmania 7250, Australia ' National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, University of Tasmania, Launceston, Tasmania 7250, Australia

Abstract: Ocean waves are the most important exciting source acting on marine structures such as ships, offshore platforms and wave energy converters. To efficiently design such structures, accurate modelling of these waves is of importance. This paper utilised a two-dimensional numerical wave tank based on the Reynolds-averaged Navier-Stokes (RANS) equations and volume of fluid (VOF) method and a commercial software code to numerically investigate ocean wave generation. Impact of different turbulence models such as standard k-ε, realisable k-ε, shear stress transport (SST) and Reynolds stress models (RSM) on the generated waves were investigated. Experimental wave measurements have been conducted to validate the numerical results. Excessive generation of eddy viscosity can lead to significant damping. Good numerical agreement with both experimental measurements and analytical wave theory was only successfully achieved either with the RSM or implementing artificial turbulence damping at the air-water interface with the SST model.

Keywords: ANSYS FLUENT; numerical wave tank; NWT; wave generation; free surface turbulence damping; shear stress transport; SST; Reynolds stress models; RSM.

DOI: 10.1504/PCFD.2017.084350

Progress in Computational Fluid Dynamics, An International Journal, 2017 Vol.17 No.3, pp.141 - 158

Received: 14 Aug 2015
Accepted: 20 Jan 2016
Published online: 06 Jun 2017 *

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