A dedicated tidal stream atlas of the stratified tidal flows near Stonecutters Bridge, Hong Kong, based on 3D numerical simulations with HLES

Morelissen, Robin; Bijlsma, Arnout C.; Tapley, M.J.

doi:10.1016/j.jher.2009.10.007

Cited by 6 publications

(3 citation statements)

References 5 publications

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“…Delft3D-Flow has been verified in several practical test cases of 3D modeling of hydrodynamics and sediment transport (Lesser et al 2004, Harcourt-Baldwin and Diedericks 2006, Morelissen et al 2010, van Rijn 2011. It was used in Part I, which described a 3D process-based model for simulating wave and tidal motions on an impermeable beach.…”

Section: Introductionmentioning

confidence: 96%

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part II: Sediment transport

Bakhtyar¹,

Dastgheib²,

Roelvink³

et al. 2016

Ocean Systems Engineering

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Abstract. This is the second of two papers on the 3D numerical modeling of nearshore hydro-and morphodynamics. In Part I, the focus was on surf and swash zone hydrodynamics in the cross-shore and longshore directions. Here, we consider nearshore processes with an emphasis on the effects of oceanic forcing and beach characteristics on sediment transport in the cross-and longshore directions, as well as on foreshore bathymetry changes. The Delft3D and XBeach models were used with four turbulence closures (viz., k-ε, k-L, ATM and H-LES) to solve the 3D Navier-Stokes equations for incompressible flow as well as the beach morphology. The sediment transport module simulates both bed load and suspended load transport of non-cohesive sediments. Twenty sets of numerical experiments combining nine control parameters under a range of bed characteristics and incident wave and tidal conditions were simulated. For each case, the general morphological response in shore-normal and shore-parallel directions was presented. Numerical results showed that the k-ε and H-LES closure models yield similar results that are in better agreement with existing morphodynamic observations than the results of the other turbulence models. The simulations showed that wave forcing drives a sediment circulation pattern that results in bar and berm formation. However, together with wave forcing, tides modulate the predicted nearshore sediment dynamics. The combination of tides and wave action has a notable effect on longshore suspended sediment transport fluxes, relative to wave action alone. The model's ability to predict sediment transport under propagation of obliquely incident wave conditions underscores its potential for understanding the evolution of beach morphology at field scale. For example, the results of the model confirmed that the wave characteristics have a considerable effect on the cumulative erosion/deposition, cross-shore distribution of longshore sediment transport and transport rate across and along the beach face. In addition, for the same type of oceanic forcing, the beach morphology exhibits different erosive characteristics depending on grain size (e.g., foreshore profile evolution is erosive or accretive on fine or coarse sand beaches, respectively). Decreasing wave height increases the proportion of onshore to offshore fluxes, almost reaching a neutral net balance. The sediment movement increases with wave height, which is the dominant factor controlling the beach face shape.

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Section: Introductionmentioning

confidence: 96%

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part II: Sediment transport

Bakhtyar¹,

Dastgheib²,

Roelvink³

et al. 2016

Ocean Systems Engineering

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“…The vertical mixing and horizontal advection also play an important role in reducing eutrophication impacts in Hong Kong waters (Ning, Chai, and Hao, 2006;Yin and Harrison, 2007). The stratification and vertical mixing of the Pearl River Estuary and Hong Kong waters in the winter dry and summer wet seasons have been studied previously (e.g., Chau and Jiang, 2001;Dong et al, 2004;Larson et al, 2005;Morelissen, Bijlsma, and Tapley, 2010;Wong et al, 2003aWong et al, , 2003b. However, little information is available about the influence of short-lived episodic events such as storms and typhoons, which may significantly influence the vertical mixing processes.…”

Section: Introductionmentioning

confidence: 99%

“…A calibrated three-dimensional (3-D) hydrodynamic model (Delft3D) for the Pearl River Estuary was applied to study the physical hydrography of Hong Kong waters and its relationship with wind events in the summer wet season, and to study stratified tidal flows in the waters of Hong Kong (see Morelissen, Bijlsma, and Tapley, 2010). In this paper, the 3-D hydrodynamic circulation and salinity structure in the partially mixed estuary are presented and discussed first.…”

Section: Introductionmentioning

confidence: 99%

Effect of Wind Speed and Direction on Summer Tidal Circulation and Vertical Mixing in Hong Kong Waters

Kuang

Lee

Harrison

et al. 2011

Journal of Coastal Research

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KUANG, C.P.; LEE, J.H.W.; HARRISON, P.J., and YIN, K.D., 2011. Effect of wind speed and direction on summer tidal circulation and vertical mixing in Hong Kong Waters. Journal of Coastal Research, 27(6A), 74-86. West Palm Beach (Florida), ISSN 0749-0208.In subtropical coastal waters around Hong Kong, a well-mixed water body is usually observed after typhoons or strong easterly wind events in summer. A calibrated three-dimensional (3-D) hydrodynamic model for the Pearl River Estuary (Delft3D) was applied to study the physical hydrography of Hong Kong waters and its relationship with wind events in the summer wet season. The general 3-D hydrodynamic circulation and salinity structure in the partially mixed estuary are presented here. The effect of wind on vertical mixing was studied for two representative wind directions (NE and SW) and three wind speeds (5, 7.5, and 10 m/s). The computations show that: (i) in general, in the summer wet season, the river plume moves into the western waters of Hong Kong due to the SW monsoon winds, and the current flow is mainly from W/SW to E/NE in the southern Hong Kong waters; the salinity vertical profile indicates that the water is strongly stratified; (ii) a strong SW wind pushes the river plume into a narrow band and decreases the salinity of the surface water in the estuary and its neighboring region; it may also enhance the mixing in the upper layer of water column, but the whole water body is still stratified; and (iii) a strong NE wind pushes the river plume westward away from Hong Kong waters, and more saline coastal waters enter Hong Kong waters; the water only becomes vertically well mixed after a 10 m/s NE wind blows for 5 d, but wind speeds of 5 and 7.5 m/s do not result in the same extent of mixing. We also examined the role of wind in an episodic storm event in August 2003. The strong SE wind from 23 to 26 August strongly mixed the water column. The moderate to weak NE wind during 16-20 August and the spring tide also contributed to the vertical mixing.www.JCRonline.org ADDITIONAL INDEX WORDS: Hydrodynamic modeling, water quality, environmental hydraulics, monsoon windinduced water transport, Hong Kong, Pearl River Estuary, wind mixing.

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Flow prediction using ENVISAT RA-2 sea surface height validated model: A case study for the effect of Hong Kong-Zhuhai-Macau Bridge in the Pearl River Estuary, China

Wai

Chen

et al. 2014

Aquatic Ecosystem Health &Amp; Management

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The Delft3D-Flow hydrodynamic model was used to predict the impact of the Hong Kong-Zhuhai-Macau Bridge on the tidal flow in the Pearl River Estuary. In addition, the impacts of the flow currents on nearby bridge piers and artificial islands were assessed. To obtain additional spatial and temporal observations relative to the tidal gauge station observations, the sea surface height, which was derived from satellite altimetry ENVISAT RA-2, was closely correlated with the simulated tidal levels on individual days. These variables were modeled in the presence and absence of the Bridge, and the sea surface height validated numerical model was used to study the impacts of the Bridge on local water levels and circulation patterns. The construction of this Bridge resulted in small changes in tidal levels in that area. The average highest and lowest tidal levels changed by less than 0.01 m, which is about 0.4% of the highest tidal level and 2% of the lowest tidal level. The total tidal range changed by nearly 0.015 m. These results indicated that coastal engineering hardly affects the tidal flow in the Pearl River Estuary. In addition, complex eddy and circulation patterns were discovered near artificial islands. It is important to understand the complex flow patterns to ensure traffic safety during bridge construction and to determine the associated impacts of the bridge on tidal currents in the Estuary.

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A dedicated tidal stream atlas of the stratified tidal flows near Stonecutters Bridge, Hong Kong, based on 3D numerical simulations with HLES

Cited by 6 publications

References 5 publications

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part II: Sediment transport

Impacts of wave and tidal forcing on 3D nearshore processes on natural beaches. Part II: Sediment transport

Effect of Wind Speed and Direction on Summer Tidal Circulation and Vertical Mixing in Hong Kong Waters

Flow prediction using ENVISAT RA-2 sea surface height validated model: A case study for the effect of Hong Kong-Zhuhai-Macau Bridge in the Pearl River Estuary, China

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