An experimental study of net sediment transport rate due to acceleration-skewed oscillatory flows over rippled seabeds

Wang, Dongxu; Yuan, Jinliang

doi:10.1016/j.coastaleng.2019.103583

Cited by 6 publications

(28 citation statements)

References 46 publications

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“…(2007), Frank-Gilchrist et al. (2018) and Wang & Yuan (2020), show that this intensified shear stress erodes sediment in the stoss side and creates a strong sediment flux toward the ripple crest and the lee side of the ripple. The thick lines in figure 16( b ) are the corresponding turbulence-averaged streamwise components of the shear stress on the ripple shown in figure 14( b ).…”

Section: Ripple Dimensions and Fluid Kinematicsmentioning

confidence: 97%

“…These sediment-laden vortices are eventually washed over the ripple crests and ejected into the water column at the opposite side of the ripple during the flow reversal. Meanwhile, sediment trapped within these vortices deposits back to the opposite side of the ripple surface, repairing the erosion that occurred on the previous half-cycle (van der Werf et al 2007;Ribberink et al 2008;Wang & Yuan 2020). The prominent vortex kinematics and the associated sediment transport processes respond rapidly to the disequilibrium in the above coordination, which eventually leads to changes in the ripple morphology.…”

Section: Introductionmentioning

confidence: 94%

“…Note that the magnitude of u 1 p2 is much larger than u 3 p2 and the corresponding velocity vector field is shown in figure 6(e). Laboratory experiments with sediment transport, such as van der Werf et al (2007), Frank-Gilchrist et al (2018 and Wang & Yuan (2020), show that this intensified shear stress erodes sediment in the stoss side and creates a strong sediment flux toward the ripple crest and the lee side of the ripple. The thick lines in figure 16(b) are the corresponding turbulence-averaged streamwise components of the shear stress on the ripple shown in figure 14(b).…”

Section: Shear Stress On Ripple Surfacementioning

confidence: 99%

“…2007; Ribberink et al. 2008; Wang & Yuan 2020). The prominent vortex kinematics and the associated sediment transport processes respond rapidly to the disequilibrium in the above coordination, which eventually leads to changes in the ripple morphology.…”

Section: Introductionmentioning

confidence: 99%

“…Madsen (1994), van Rijn (2007), van der A et al. (2013) and Wang & Yuan (2020). Using friction factor, predictors (O'Donoghue et al.…”

Section: Introductionmentioning

confidence: 99%

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Selection of vortex ripple dimensions in sinusoidal oscillatory flows. Part 1. Ripple dimensions and fluid kinematics

2023

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Subaqueous vortex ripples in equilibrium are characterized by their unique geometry and dimensions. Motivated by the recent direct numerical simulation study of oscillatory turbulent flow over a wavy bottom by Önder & Yuan (J. Fluid Mech., vol. 858, 2019, pp. 264–314), the objective of this study is to further investigate the fluid dynamical controls that determine the distinctive equilibrium dimensions of vortex ripples. We use direct numerical simulations to investigate the differences in flow kinetics between sinusoidal oscillatory flow over equilibrium and out-of-equilibrium vortex ripples. In comparison with the equilibrium case, the spanwise coherent vortices, the averaged bottom shear stress on overlying flow and the shear stress distribution on the ripple surface are identified as the key fluid dynamical controls on equilibrium dimensions. Based on these controls, we propose mechanisms in the selection of vortex ripple dimensions. We observe that the flow adjusts in such a way that the interaction between overlying flow and vortex ripples tends to generate the strongest coherent vortices while the ripple surface (or overlying flow) experiences the smallest shear stress averaged over ripple wavelength during the selection process. Through a triple decomposition of the flow, the component of the ripple-induced fluctuation is found to dictate these fluid dynamical controls, which implies that this component plays an important role in the evolution of vortex ripples.

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Section: Ripple Dimensions and Fluid Kinematicsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 94%