scholarly journals SECONDARY SAND TRANSPORT MECHANISMS

1980 ◽  
Vol 1 (17) ◽  
pp. 68
Author(s):  
A.W. Smith ◽  
A.D. Gordon
Keyword(s):  
Work Capacity ◽  
Sand Transport ◽  
Primary Process ◽  
Transport Mechanisms ◽  
Littoral Drift ◽  
Transport Mode ◽  
Primary Mechanism ◽  
Beach Sediments ◽  
Individual Contributions ◽  
Hydraulic Processes

The basic concept of coastal littoral drift consisting of a "river" of sand driven by the direct alongshore component of oblique waves has long been considered as a basis for littoral transport equations. This concept however is highly simplified since the actual littoral drift on real beaches represents only the final result of the inter-action of dozens or perhaps hundreds of secondary hydraulic processes which continuously occur in Nature. On many Coasts littoral transport is taken to represent the primary mechanism of beach recession or build-up but many of the secondary mechanisms themselves are only partially understood and their individual contributions to the primary process largely unexplored. This paper therefore discusses some of these secondary processes and since offshore- onshore sediment transport is probably the most important of these a mechanism for this transport mode is suggested based upon the interaction between wave energy and a work capacity parameter for the beach sediments.

A PETBOGRAPHIC STUDY ON LITTORAL DRIFT ALONG THE ISHIKAWA COAST, JAPAN

1966 ◽  
Vol 1 (10) ◽  
pp. 35
Author(s):  
Makoto Aramaki ◽  
Shigemi Takayama
Keyword(s):  
Longitudinal Variation ◽  
Southern Coast ◽  
Littoral Drift ◽  
Beach Sediments ◽  
Prevailing Direction ◽  
Ishikawa Prefecture

Based on the longitudinal variation series in various properties of beach sediments and topographic profiles along the southern coast of Ishikawa Prefecture, Japan, the prevailing direction and mechanism of littoral drift are discussed.

Experimental Study on Particle Behaviour in Simulated Gas-Oil-Sand Multiphase Production and Transfer Operations

2006 ◽  
Author(s):  
O. O. Bello ◽  
K. M. Reinicke ◽  
C. Teodoriu
Keyword(s):  
Multiphase Flows ◽  
Particle Interaction ◽  
Flow Regimes ◽  
Sand Particle ◽  
Experimental Investigations ◽  
Sand Transport ◽  
Transport Mechanisms ◽  
Oil Sand ◽  
Transport Behaviour ◽  
Oil Gas

A crucial point still to be established in the prediction of oil-gas-sand multiphase production and transfer system performance is the identification of relevant mechanisms describing sand particle transport. To resolve this issue, experimental investigations are made on the behaviour of suspended sand particles in simulated oil-gas-sand multiphase pipe flows paying attention to the time-averaged local and global sand velocity and holdup. Simultaneous measurements of the time-averaged local and global sand velocity are made by digital imaging technique for better understanding of the oil-gas-sand multiphase flow hydrodynamics and sand transport mechanisms. The results show flow regimes of the multiphase flows significantly influence sand transport in the pipeflow. The shape of the local and global sand particle velocity and holdup profiles are also strongly modified by flow regimes. Furthermore, the experimental results indicate that the transport effect of the suspended sand particle can be enhanced by operating the multiphase flows under slug flow conditions. It is concluded that a new mechanism based on bubble-particle interaction needs to be considered in the modelling of sand transport behaviour during oil-gas-sand multiphase production and transfer operations.

Near-Bed Sand Transport Mechanisms under Waves— A Large-Scale Flume Experiment (Sistex99)

2001 ◽  
Author(s):  
Jan S. Ribberink ◽  
C. Marjolein Dohmen-Janssen ◽  
Daniel M. Hanes ◽  
Steve R. McLean ◽  
Chris Vincent
Keyword(s):  
Large Scale ◽  
Sand Transport ◽  
Flume Experiment ◽  
Transport Mechanisms

scholarly journals QUANTIFICATION OF LONGSHORE SAND TRANSPORT

1988 ◽  
Vol 1 (21) ◽  
pp. 205
Author(s):  
John S. Yeend ◽  
Darryl J. Hatheway
Keyword(s):  
Sand Transport ◽  
Palm Beach County ◽  
The South ◽  
Littoral Drift ◽  
Pumping Rates

The intent of this paper is to express the quantities of sand bypassed by a sand transfer facility and transported in the littoral drift at the South Lake Worth Inlet, Palm Beach County, Florida. Discussion on littoral transport volumes will include estimates of the annual average drift from 1948 to 1987, and discussions of sand bypassing quantities will include improvements in the estimation of pumping rates.

scholarly journals Sedimentologia y Mineralogia de Playas de la Peninsula Valdes y el Golfo Nuevo (Chubut - Argentina)

1997 ◽  
Vol 24 (1-2) ◽  
pp. 39
Author(s):  
E. M. GELOS ◽  
J. O. SPAGNUOLO ◽  
R. A. SHILLIZZI ◽  
E.A. GOMEZ
Keyword(s):  
Dynamical Behavior ◽  
Energy Conditions ◽  
Local Dynamic ◽  
Littoral Drift ◽  
Sandy Gravel ◽  
Mineralogical Characteristics ◽  
Normal Behavior ◽  
Beach Sediments ◽  
High Concentrations ◽  
Maturity Degree

Beach sediments of the area under study have the following textural characteristics: 59% correspond to fine sands; in lower proportion we can find medium and coarse sands; 40% are gravel and sandy gravel; 1% include the politic fraction. Log-probabilistic curves show a general normal behavior in textural distribution. The predominant sorting is moderate indicating an intermediate maturity degree. Mineralogical characteristics are: minerals present belong to the “pampeano-patagónica” association; high concentrations of glass and garnet have been observed in some areas and this can be attributed to local dynamic conditions; using the grouping statistical analysis three groups were established and their characteristics would indicate a distributive tendency related to energy conditions of each environment; the gulfs dynamical behavior would depends on the coastal topography and on wind influences over littoral drift.

scholarly journals Identifying sediment transport mechanisms from grain size-shape distributions

2019 ◽  
Author(s):  
Johannes Albert van Hateren ◽  
Unze van Buuren ◽  
Sebastiaan Martinus Arens ◽  
Ronald Theodorus van Balen ◽  
Maarten Arnoud Prins
Keyword(s):  
Grain Size ◽  
Spatial Distribution ◽  
Sediment Transport ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Grain Shape ◽  
Transport Processes ◽  
Transport Mechanisms ◽  
Aeolian Transport ◽  
Transport Mode

Abstract. The way in which sediment is transported (creep, saltation, suspension), is traditionally interpreted from grain size distribution characteristics. However, the grain size range associated with transitions from one transport mode to the other is highly variable because it depends on the amount of transport energy available. In this study we present a novel methodology for determination of the sediment transport mode based on grain size and shape data from dynamic image analysis. The data are integrated into grain size-shape distributions and primary components are determined using end-member modelling. In real-world datasets, primary components can be interpreted in terms of different transport mechanisms and/or sediment sources. Accuracy of the method is assessed using artificial datasets with known primary components that are mixed in known proportions. The results show that the proposed technique accurately identifies primary components with the exception of those primary components that only form minor contributions to the samples (highly mixed components). The new method is also tested on sediment samples from an active aeolian system in the Dutch coastal dunes. Aeolian transport processes and geomorphology of these type of systems are well known and can therefore be linked to the spatial distribution of end members to assess the physical significance of the method's output. The grain size-shape distributions of the dune dataset are unmixed into three primary components. The spatial distribution of these components is constrained by geomorphology and reflects the three dominant aeolian transport processes known to occur along a beach-dune transect: bedload on the beach and in notches that were dug by man through the shore-parallel foredune ridge, modified saltation on the windward and leeward slope of the intact foredune, and suspension in the vegetated hinterland. The three transport modes are characterised by distinctly different trends in grain shape with grain size: with increasing size, bedload shows a constant grain regularity, modified saltation a minor decrease in grain regularity and suspension a strong decrease in grain regularity. These trends, or in other words, the shape of the grain size-shape distributions, can be used to determine the transport mode responsible for a sediment deposit. Results of the method are therefore less ambiguous than those of traditional grain-size distribution end-member modelling, especially if multiple transport modes occur or if primary components overlap in terms of grain size but differ in grain shape.

scholarly journals ECO-SYSTEM BASED BEACH EROSION CONTROL BY BERM NOURISHMENT COMBINED WITH BURIED SAND TUBE

2018 ◽  
pp. 102
Author(s):  
Shinji Sato ◽  
Keisuke Murakami ◽  
Kunihiro Watanabe ◽  
Yuuichi Okamura ◽  
Shin Hashimoto ◽  
...  
Keyword(s):  
River Mouth ◽  
Erosion Control ◽  
Beach Erosion ◽  
Sand Transport ◽  
Wave Direction ◽  
Large Variability ◽  
Longshore Transport ◽  
The Pacific ◽  
Beach Sediments ◽  
Sand Nourishment

Miyazaki Coast is a 10 km stretch sandy beach between the Miyazaki Port and the Hitotsuse River, located south of Japan facing the Pacific Ocean. Significant beach erosion has been observed owing to the entrapment of sand in the harbor area and the blockage of longshore sand transport by the river mouth jetties. Sato et al. (ICCE 2010) estimated that the direction of the long-term longshore sand transport is to the southward on the basis of thermo-luminescence measurement of beach sediments. Continuous bathymetry surveys indicated the southward longshore sand transport rate at 200 thousand m3/year. However, a large variability of the incident wave direction suggested the variability in the direction of the longshore transport. Occasional attacks of typhoon storms appeared to accelerate the erosion. As a countermeasure to mitigate the erosion, sand nourishment has been introduced since 2008 with the amount of 50 to 80 thousand m3/year. Three groins were constructed to decrease the longshore transport. However, further erosion has been observed by typhoon storms even on the nourished area. This paper describes the results of on-site monitoring of waves, currents and topography change to understand the role of typhoon storms in beach erosion and to investigate the performance of eco-system based erosion control works.

scholarly journals Identifying sediment transport mechanisms from grain size–shape distributions, applied to aeolian sediments

2020 ◽  
Vol 8 (2) ◽  
pp. 527-553
Author(s):  
Johannes Albert van Hateren ◽  
Unze van Buuren ◽  
Sebastiaan Martinus Arens ◽  
Ronald Theodorus van Balen ◽  
Maarten Arnoud Prins
Keyword(s):  
Grain Size ◽  
Spatial Distribution ◽  
Sediment Transport ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Grain Shape ◽  
Transport Processes ◽  
Transport Mechanisms ◽  
Aeolian Transport ◽  
Transport Mode

Abstract. The way in which sediment is transported (creep, saltation, suspension), is traditionally interpreted from grain size distribution characteristics. However, the grain size range associated with transitions from one transport mode to the other is highly variable because it depends on the amount of transport energy available. In this study we present a novel methodology for determination of the sediment transport mode based on grain size and shape data from dynamic image analysis. The data are integrated into grain size–shape distributions, and primary components are determined using endmember modelling. In real-world datasets, primary components can be interpreted in terms of different transport mechanisms and/or sediment sources. Accuracy of the method is assessed using artificial datasets with known primary components that are mixed in known proportions. The results show that the proposed technique accurately identifies primary components, with the exception of those primary components that only form minor contributions to the samples (highly mixed components). The new method is tested on sediment samples from an active aeolian system in the Dutch coastal dunes. Aeolian transport processes and geomorphology of these type of systems are well known and can therefore be linked to the spatial distribution of endmembers to assess the physical significance of the method's output. The grain size–shape distributions of the aeolian dune dataset are unmixed into three primary components. The spatial distribution of these components is constrained by geomorphology and reflects the three dominant aeolian transport processes known to occur along a beach–dune transect: bedload on the beach and in notches that were dug by man through the shore-parallel foredune ridge, modified saltation on the windward and leeward slope of the intact foredune, and suspension in the vegetated hinterland. The three transport modes are characterised by distinctly different trends in grain shape with grain size: with increasing size, bedload shows a constant grain regularity, modified saltation a minor decrease in grain regularity, and suspension a strong decrease in grain regularity. These trends, or in other words, the shape of the grain size–shape distributions, can be used to determine the transport mode responsible for an aeolian sediment deposit. Results of the method are therefore less ambiguous than those of traditional grain size distribution endmember modelling, especially if multiple transport modes occur or if primary components overlap in terms of grain size but differ in grain shape.

scholarly journals EROSION PROBLEMS OF THE DUTCH ISLAND OF GOEREE

1974 ◽  
Vol 1 (14) ◽  
pp. 71
Author(s):  
H.G.H. Ten Hoopen Krueger ◽  
W.T. Bakker
Keyword(s):  
Sand Transport ◽  
Littoral Drift ◽  
The West ◽  
West Side ◽  
Delta Area ◽  
Dutch Coast ◽  
South West ◽  
Tidal Estuaries ◽  
Before And After ◽  
Wave Induced

At many places along the Dutch coast especially at the West side of the islands, erosion occurs. One of the islands where the erosion is severe, is Goeree, situated in the Delta area in the South-West of the Netherlands. (see fig. 1). This isle is recently connected with other islands by dams, (see fig.2). These dams built within the scope of the Delt aproject plans closing the tidal estuaries and to shorten the length of the coastline thus reducing the wave attack. This paper examines how the influences of the closure of the estuaries affect on the erosion of the neighbouring coast. To this end, the changes in vertical and horizontal tide caused by the closure as well as the wave induced littoral drift and the sand transport caused by a combination of tidal currents and waves before and after the closure, are computed. On the basis of this computations, a few suitable solutions for the reduction of erosion are discussed.

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