scholarly journals Numerical modelling of intra-wave sediment transport on sandy beaches using a non-hydrostatic, wave-resolving model

2020 ◽  
Vol 71 (1) ◽  
pp. 1-20
Author(s):  
Giulia Mancini ◽  
Riccardo Briganti ◽  
Robert McCall ◽  
Nicholas Dodd ◽  
Fangfang Zhu
Keyword(s):  
Sediment Transport ◽  
Numerical Modelling ◽  
Large Scale ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Swash Zone ◽  
Transport Modelling ◽  
Wave Trains ◽  
Sediment Transport Modelling

AbstractThe mutual feedback between the swash zone and the surf zone is known to affect large-scale morphodynamic processes such as breaker bar migration on sandy beaches. To fully resolve this feedback in a process-based manner, the morphodynamics in the swash zone and due to swash-swash interactions must be explicitly solved, e.g., by means of a wave-resolving numerical model. Currently, few existing models are able to fully resolve the complex morphodynamics in the swash zone, and none is practically applicable for engineering purposes. This work aims at improving the numerical modelling of the intra-wave sediment transport on sandy beaches in an open-source wave-resolving hydro-morphodynamic framework (e.g., non-hydrostatic XBeach). A transport equation for the intra-wave suspended sediment concentration, including an erosion and a deposition rate, is newly implemented in the model. Two laboratory experiments involving isolated waves and wave trains are simulated to analyse the performance of the model. Numerical results show overall better performance in simulating single waves rather than wave trains. For the latter, the modelling of the morphodynamic response improves in the swash zone compared with the existing sediment transport modelling approach within non-hydrostatic XBeach, while the need of including additional physical processes to better capture sediment transport and bed evolution in the surf zone is highlighted in the paper.

scholarly journals ANALYSIS OF THE PERFORMANCE OF DIFFERENT SEDIMENT TRANSPORT FORMULATIONS IN NON-HYDROSTATIC XBEACH

2020 ◽  
pp. 35
Author(s):  
Giulia Mancini ◽  
Riccardo Briganti ◽  
Gioele Ruffini ◽  
Robert McCall ◽  
Nicholas Dodd ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Sandy Beaches ◽  
Sediment Dynamics ◽  
Wave Flow ◽  
Swash Zone ◽  
Transport Modelling ◽  
Morphological Response ◽  
Wave Trains ◽  
Sediment Transport Modelling ◽  
Bed Changes

Process-based, wave-resolving models are essential tools to resolve the complex hydro-morphodynamics in the swash zone. The open-source Non-Hydrostatic XBeach model can solve the depth-averaged wave-by-wave flow in the nearshore region up to the shoreline and the intra-wave bed changes during time-varying storms. However, validation and testing of its morphological response are still limited in the context of sandy beaches. This work aims to assess the performance of the wave-resolving sediment dynamics modelling within Non-Hydrostatic XBeach for different sediment transport formulations. The sediment transport modelling approaches considered in this study were tested and compared to laboratory experiments involving wave trains over an intermediate beach. Numerical results show a better performance in the prediction of the intra-swash sediment dynamics when the newly implemented wave resolving transport equation is applied compared to the existing approach within the model.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/2sy-Dr8iJ1M

scholarly journals APPLICABILITY OF SUSPENDED SEDIMENT CONCENTRATION FORMULAE TO LARGE-SCALE BEACH MORPHOLOGICAL CHANGES

2012 ◽  
Vol 1 (33) ◽  
pp. 57 ◽  
Author(s):  
Ravindra Jayaratne ◽  
Yasufumi Takayama ◽  
Tomoya Shibayama
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Surf Zone ◽  
Morphological Changes ◽  
Current Model ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Propagation Model ◽  
Deformation Model ◽  
Seabed Sediment

Study of beach morphological changes under storm conditions and its prediction capability are of paramount importance in coastal zone management. Seabed sediment is picked up violently in and outside the surf zone due to suspension mechanisms, therefore a considerable amount of sand is transported in coastal waters due to such mechanisms. For the construction of an accurate beach morphological model, it is necessary to elucidate the sediment suspension and to introduce it properly into the modelling of sediment transport. Jayaratne and Shibayama (2007) developed a complete set of explicit theoretical formulae to predict the time-averaged concentration on sandy beaches due to three suspension mechanisms: a) vortical motion over wave-generated sand ripples, b) from sheet flow, and c) turbulent motion under breaking waves. The present paper focuses on the development of a quasi-3D beach deformation model using the sediment concentration models of Jayaratne and Shibayama (2007), the bed load model of Watanabe (1982), the wave propagation model of Onaka et al. (1988), the nearshore current model of Philips (1977) and the undertow model of Okayasu et al. (1990) to predict the large-scale morphodynamics of sandy beaches. The predicted beach profiles and total sediment transport rates were compared with two sets of large-scale laboratory experimental data [Kajima et al. (1983); Kraus and Larson (1988)] and Seisho beach at Kanagawa Prefecture, Japan. It can be concluded that the present numerical model is capable of predicting sediment transport direction, on-offshore sand bar formation and the general trend of the beach profiles of large-scale erosive- and accretive-type sandy beaches to a satisfactory level.

scholarly journals Surf Zone Turbulence and Suspended Sediment Dynamics—A Review

2021 ◽  
Vol 9 (11) ◽  
pp. 1300
Author(s):  
Troels Aagaard ◽  
Joost Brinkkemper ◽  
Drude F. Christensen ◽  
Michael G. Hughes ◽  
Gerben Ruessink
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Sandy Beaches ◽  
Suspended Sediment Transport ◽  
Velocity Signal ◽  
Wave Phase ◽  
Turbulence Production

The existence of sandy beaches relies on the onshore transport of sand by waves during post-storm conditions. Most operational sediment transport models employ wave-averaged terms, and/or the instantaneous cross-shore velocity signal, but the models often fail in predictions of the onshore-directed transport rates. An important reason is that they rarely consider the phase relationships between wave orbital velocity and the suspended sediment concentration. This relationship depends on the intra-wave structure of the bed shear stress and hence on the timing and magnitude of turbulence production in the water column. This paper provides an up-to-date review of recent experimental advances on intra-wave turbulence characteristics, sediment mobilization, and suspended sediment transport in laboratory and natural surf zones. Experimental results generally show that peaks in the suspended sediment concentration are shifted forward on the wave phase with increasing turbulence levels and instantaneous near-bed sediment concentration scales with instantaneous turbulent kinetic energy. The magnitude and intra-wave phase of turbulence production and sediment concentration are shown to depend on wave (breaker) type, seabed configuration, and relative wave height, which opens up the possibility of more robust predictions of transport rates for different wave and beach conditions.

scholarly journals Review of Suspended Sediment Transport Mathematical Modelling Studies

Fluids ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 23
Author(s):  
Joseph T. Wallwork ◽  
Jaan H. Pu ◽  
Snehasis Kundu ◽  
Prashanth R. Hanmaiahgari ◽  
Manish Pandey ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Particle Density ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Threshold Velocity ◽  
Transport Modelling ◽  
Modelling Studies ◽  
Rouse Number ◽  
Sediment Transport Modelling

This paper reviews existing studies relating to the assessment of sediment concentration profiles within various flow conditions due to their importance in representing pollutant propagation. The effects of sediment particle size, flow depth, and velocity were considered, as well as the eddy viscosity and Rouse number influence on the drag of the particle. It is also widely considered that there is a minimum threshold velocity required to increase sediment concentration within a flow above the washload. The bursting effect has also been investigated within this review, in which it presents the mechanism for sediment to be entrained within the flow at low average velocities. A review of the existing state-of-the-art literature has shown there are many variables to consider, i.e., particle density, flow velocity, and turbulence, when assessing the suspended sediment characteristics within flow; this outcome further evidences the complexity of suspended sediment transport modelling.

scholarly journals CROSS-SHORE SEDIMENT TRANSPORT IN THE SWASH ZONE: LARGE-SCALE LABORATORY EXPERIMENTS

2020 ◽  
pp. 18
Author(s):  
Sara Dionisio Antonio ◽  
Jebbe van der Werf ◽  
Bart Vermeulen ◽  
Ivan Caceres ◽  
Jose M. Alsina ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Surf Zone ◽  
Transport Processes ◽  
Sand Transport ◽  
Swash Zone ◽  
Flume Experiments ◽  
Wave Flume ◽  
Shoreline Evolution

The swash zone is a highly dynamic boundary between the beach and the surf zone. Swash processes determine whether sediment is either stored on the upper beach or is transported offshore, and thus strongly affect shoreline evolution. The present research focuses on the hydrodynamics, sand transport processes and net sediment transport in the swash zone through a series of large-scale wave flume experiments. This research aims to improve the understanding of swash zone sand transport processes, in particular the role of cross-shore sand advection and wave-swash interactions, and bring new detailed insights into the relation between intra-swash processes and net sand transport rates.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/tYvJ0pML-kU

scholarly journals On integrated sediment transport modelling for flash events in mountain environments

2011 ◽  
Vol 60 (1) ◽  
pp. 191-213 ◽  
Author(s):  
Alessio Radice ◽  
Elisa Giorgetti ◽  
Davide Brambilla ◽  
Laura Longoni ◽  
Monica Papini
Keyword(s):  
Sediment Transport ◽  
Transport Modelling ◽  
Mountain Environments ◽  
Sediment Transport Modelling

Coupled fluid dynamics-sediment transport modelling of a Crater Lake break-out lahar: Mt. Ruapehu, New Zealand

2010 ◽  
Vol 388 (3-4) ◽  
pp. 399-413 ◽  
Author(s):  
Jonathan L. Carrivick ◽  
Vern Manville ◽  
Alison Graettinger ◽  
Shane J. Cronin
Keyword(s):  
Fluid Dynamics ◽  
New Zealand ◽  
Sediment Transport ◽  
Crater Lake ◽  
Transport Modelling ◽  
Sediment Transport Modelling

scholarly journals 2D Sediment Transport Modelling in High Energy River – Application to Var River, France

2016 ◽  
Vol 154 ◽  
pp. 536-543 ◽  
Author(s):  
Elodie Zavattero ◽  
Mingxuan Du ◽  
Qiang Ma ◽  
Olivier Delestre ◽  
Philippe Gourbesville
Keyword(s):  
Sediment Transport ◽  
High Energy ◽  
Transport Modelling ◽  
Sediment Transport Modelling

scholarly journals One-dimensional sediment transport modelling with Engelund–Hansen and Ackers–White transport equations for the Lower Danube River

2021 ◽  
pp. 103-117
Author(s):  
Davor Kvočka
Keyword(s):  
Sediment Transport ◽  
Negative Impact ◽  
Statistical Tests ◽  
Field Measurements ◽  
River Basin Management ◽  
Transport Equations ◽  
Danube River ◽  
Transport Modelling ◽  
1D Modelling ◽  
Sediment Transport Modelling

Sediment transport can have a negative impact on riparian environments, as it can lead to the deterioration of ecological diversity and increase flood risks. Sediment transport modelling is thus a key tool in river basin management and the development of river training structures. In this study, we examined the appropriateness of 1D modelling for total sediment transport loads using the Engelund–Hansen and Ackers–White transport equations for the Lower Danube River. The study evaluated the effect of sediment grading on the accuracy of 1D model results, the appropriateness of 1D sediment transport modelling within technical or engineering projects, and the appropriateness of the Engelund–Hansen and Ackers–White equations for estimating sediment yield in the area of the Lower Danube River. The model results have been compared to field measurements, with the accuracy of the modelling results being evaluated with statistical tests. The obtained results show: (i) the sediment grading does not have a significant impact on the 1D modelling results, (ii) 1D sediment transport modelling gives sufficiently accurate results for practical engineering use (e.g. the estimation of dredging activities), and (iii) the Engelund–Hansen equation is generally better for sediment transport modelling in the Lower Danube River.

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