CFD-based methods for numerical modelling of scour

Abstract

Marine local scour is understood as the removal of sediment from around the base of an object on the seabed caused by waves and currents. The introduction of a flow obstruction to the seafloor will have a significant impact on the local hydrodynamics, causing acceleration, pressure gradients, boundary-layer separation and increased turbulence at the seabed and in the wake of the object. Where the seabed cannot resist the increased magnitude of impinging shear forces, e.g. in non-cohesive mobile sediment such as sands, sediment will be eroded to form a characteristic scour hole. Scour, left unchecked can cause structural damage and major economic losses. The ability to predict scour, both vertical and lateral, is thus a prerequisite for the optimised design of a structure and provision of scour protection.
At present, empirical equations are used for simple two-dimensional objects such as vertical and horizontal cylindrical type in the forecast of maximum scour depths. Fewer relations are available for the quantification lateral scour extent and evolution of the scour pit with time. For a more comprehensive scour prediction or assessment of more complex structures, expensive and time-consuming physical model experiments are required.

The aim of this PhD project is to develop a numeric method for scour modelling in openFOAM CFD which will be capable of predicting scour around complex three-dimensional seabed structures. In this study, we will focus on the discussion of the available approaches for scour modelling using CFD methods.

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Identifiers

ORCID for J.K. Dix: orcid.org/0000-0003-2905-5403

ORCID for S.R. Turnock: orcid.org/0000-0001-6288-0400

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