Toward Improving Prediction of Sediment Transport over Wave-Induced Ripples

TL;DR

This paper develops and validates simple analytical models for predicting sediment transport over wave-induced ripples, incorporating eddy viscosity profiles that depend on wave non-linearity, to improve prediction accuracy in coastal engineering.

Contribution

It introduces a practical analytical tool for modeling eddy viscosity profiles in oscillatory boundary layers, validated against DNS data and the baseline k-ω model.

Findings

Eddy viscosity in oscillatory boundary layers can be described by a simple analytical formulation.

The vertical eddy viscosity profile shape is validated for sinusoidal and asymmetric waves.

The eddy viscosity profile depends on wave non-linearity, requiring specific calibration.

Abstract

Sediment transport over wave-induced ripples is a very complex phenomenon where available models fail to provide accurate predictions. For coastal engineering applications, the 1-DV advection-diffusion equation could be used with an additional parameter {\alpha} related to the process of vortex shedding above ripples (Absi, 2010). The aim of this study is to provide simple practical analytical tools. An analytical eddy viscosity profile was validated by DNS data of turbulent channel flows (Absi et al., 2011). In this study, we will show that: (1) the period-averaged eddy viscosity in oscillatory boundary layers could be described by this simple analytical formulation; (2) The shape of the vertical profile is validated by period-averaged eddy viscosity of baseline (BSL) k-{\omega} model (Suntoyo and Tanaka, 2009) for sinusoidal and asymmetric waves; (3) The vertical eddy viscosity profile depends on the wave non-linearity parameter and requires therefore a specific calibration.