scholarly journals DISTRIBUTION OF SAND TRANSPORT RATE ACROSS A SURF ZONE

1978 ◽  
Vol 1 (16) ◽  
pp. 95 ◽  
Author(s):  
Toru Swaragi ◽  
Ichiro Deguchi
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Surf Zone ◽  
Transport Rate ◽  
Sand Transport ◽  
Shear Stresses ◽  
Bottom Shear Stress ◽  
Longshore Current ◽  
Unidirectional Flow ◽  
Longshore Sediment Transport

The distributions of longshore and on-offshore sediment transport rates in a surf zone were measured by an apparatus which was able to separately record both components of the sediment transport rate,, The characteristics of their distributions were discussed from the bottom shear stresses which were measured by the shear meter under the same wave conditions as the laboratory experiment of the sediment transport. The maximum bottom shear stress took place at the depth between the breaking depth of waves and the depth where the velocity of the longshore current showed a maximum. On the other hand, the maximum on-offshore and longshore sediment transport rates occured at the depth slightly shallower than the depth where the maximum bottom shear stress took place. What's more, the longshore sediment transport rates were represented by the longshore current velocity and the bottom shear stress generated by waves and the longshore current. However, the distribution of the on-offshore sediment transport rates showed more complicated profile than that of the longshore sediment transport rates because there were no eminent unidirectional flow in the direction normal to the shore line. Therefore, the on-offshore sediment transport rates could not be formulated by the bottom shear stresses.

scholarly journals TOWARD AN IMPROVED EMPIRICAL FORMULA FOR LONGSHORE SAND TRANSPORT

1988 ◽  
Vol 1 (21) ◽  
pp. 88 ◽  
Author(s):  
Nicholas C. Kraus ◽  
Kathryn J. Gingerich ◽  
Julie Dean Rosati
Keyword(s):  
Oscillatory Flow ◽  
Field Experiments ◽  
Surf Zone ◽  
Transport Rate ◽  
Sand Transport ◽  
Longshore Current ◽  
Wave Energy Dissipation ◽  
Total Transport ◽  
Local Wave ◽  
Correction Terms

This paper presents results of two field experiments performed using portable traps to obtain point measurements of the longshore sand transport rate in the surf zone. The magnitude of the transport rate per unit width of surf zone is found to depend on the product of the local wave height and mean longshore current speed, but correlation is much improved by including two correction terms, one accounting for local wave energy dissipation and the other for the fluctuation in the longshore current. The field transport rates are also found to be compatible with laboratory rates obtained under combined unidirectional and oscillatory flow. Total transport rates previously reported for this experiment program are revised with recently determined sand trapping efficiencies.

scholarly journals LONGSHORE SEDIMENT TRANSPORT RATE vs. CROSS - SHORE DISTRIBUTION OF SEDIMENT GRAIN SIZES

1988 ◽  
Vol 1 (21) ◽  
pp. 145
Author(s):  
C.I. Moutzouris
Keyword(s):  
Grain Size ◽  
Sediment Transport ◽  
Transport Rate ◽  
Longshore Current ◽  
Sediment Grain Size ◽  
Grain Sizes ◽  
Sediment Transport Rate ◽  
Power Equation ◽  
Longshore Sediment Transport ◽  
The Cross

Existing models for longshore sediment transport rate computations assume the sediment grain size and grain sizerelated parameters to be uniform in both the cross-shore and longshore directions. Field results from tideless beaches, which are briefly described in the paper, show that the latter change in both directions due to changing wave energylevels. The sensitivity analysis described in the paper shows that both longshore current and transport rate computations are sensitive to the cross-shore changes in grain size.Finally, a modified linearity coefficient for the wave power equation is proposed based upon the cross-shore distributions of grain size as found in nature.

scholarly journals PREDICTION OF SEDIMENT TRANSPORT DUE TO IRREGULAR WAVE MOTION

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Taufiqur Rachman ◽  
Suntoyo Suntoyo
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Transport Rate ◽  
Irregular Waves ◽  
Bottom Shear Stress ◽  
Coastal Morphology ◽  
New Approach ◽  
Irregular Wave ◽  
Sediment Transport Rate ◽  
Rough Bed

<p>In general, waves in coastal environments are irregular and have a random shape with a height and period that was not constant. The accuracy of sediment transport rate prediction is the most important stages in the study of morphology and coastal marine environments. In addition, the predictive model of coastal morphology is more efficient to use the bottom shear stress calculation approach for practical purposes rather than a more complex approach to the modeling of two phases. In this paper, the calculation of sediment transport was based on the bottom shear stress modelling purposed with data validation from the experimental results in the turbulent bottom boundary layer over rough bed under irregular waves. The new approach to estimate the bottom shear stress was based on combining velocity and acceleration terms. Furthermore, a new approach of the bottom shear stress was applied to formulate the sheet flow sediment transport rate for irregular waves by using the experimental data from Dibadjnia and Watanabe (1998) and the empirical formula was found.</p> <p>Keywords: sediment transport, bottom shear stress, irregular waves</p>

scholarly journals FIELD EXPERIMENTS ON LONGSHORE SAND TRANSPORT IN THE SURF ZONE

1982 ◽  
Vol 1 (18) ◽  
pp. 61 ◽  
Author(s):  
Nicholas C. Kraus ◽  
Masahiko Isobe ◽  
Hajime Igarashi ◽  
Tamio O. Sasaki ◽  
Kiyoshi Horikawa
Keyword(s):  
Current Velocity ◽  
Field Experiments ◽  
Surf Zone ◽  
Transport Rate ◽  
Sand Transport ◽  
Breaking Wave ◽  
Longshore Current ◽  
Mixing Depth ◽  
Sand Transport Rate ◽  
Advection Velocity

Eight fluorescent sand tracer experiments were performed in energetic surf zones on natural beaches and on beaches near structures to measure the short-term longshore sand transport rate. Tracer of up to four distinct colors was injected on a line crossing the surf zone to investigate the on-offshore distributions of the longshore sand adveetion velocity and transport rate. The tracer advection velocity, v , and the depth of mixing into the bed, b, were determined from large numbers of cores taken in situ throughout the sampling area. The sand advection velocity and mixing depth were not constant across the surf zone, but usually exhibited a maximum either toward the shoreline or toward the breaker line, or in both regions. The local breaking wave height, H. , and horizontal current velocity in the surf zone (yielding an average longshore current velocity V) were also measured. The data were interpreted with simple dimensional arguments to give the following results: b = 0.027 H,, v = 0.011 V, and the volumetric transport rate Q = 0.024 H V. Agreement was also found between the measured total longshore sand transport rate and a predictive expression due to Bagnold involving the breaking wave power and average longshore current velocity. Although the results appear reasonable and consistent, a problem remains concerning the apparent decrease in tracer advection speed alongshore recorded in most experiments at the longer sampling times.

scholarly journals PREDICTION OF SEDIMENT TRANSPORT DUE TO IRREGULAR WAVE MOTION

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Taufiqur Rachman ◽  
Suntoyo Suntoyo
Keyword(s):  
Shear Stress ◽  
Sediment Transport ◽  
Transport Rate ◽  
Irregular Waves ◽  
Bottom Shear Stress ◽  
Coastal Morphology ◽  
New Approach ◽  
Irregular Wave ◽  
Sediment Transport Rate ◽  
Rough Bed

In general, waves in coastal environments are irregular and have a random shape with a height and period that was not constant. The accuracy of sediment transport rate prediction is the most important stages in the study of morphology and coastal marine environments. In addition, the predictive model of coastal morphology is more efficient to use the bottom shear stress calculation approach for practical purposes rather than a more complex approach to the modeling of two phases. In this paper, the calculation of sediment transport was based on the bottom shear stress modelling purposed with data validation from the experimental results in the turbulent bottom boundary layer over rough bed under irregular waves. The new approach to estimate the bottom shear stress was based on combining velocity and acceleration terms. Furthermore, a new approach of the bottom shear stress was applied to formulate the sheet flow sediment transport rate for irregular waves by using the experimental data from Dibadjnia and Watanabe (1998) and the empirical formula was found. Keywords: sediment transport, bottom shear stress, irregular waves

scholarly journals DISTRIBUTION OF SEDIMENT TRANSPORT ACROSS THE SURF ZONE

1972 ◽  
Vol 1 (13) ◽  
pp. 52 ◽  
Author(s):  
Edward B. Thornton
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Sand Transport ◽  
Bed Load ◽  
Relative Distribution ◽  
Longshore Current ◽  
Energy Principle ◽  
Load Transport ◽  
Bed Load Transport ◽  
Wave Induced

The wave-induced sand transport alongshore is investigated by an energy principle approach. Although the energy approach has been used before, this is the first application to comparing theory and measurements of the distribution of littoral transport along a line perpendicular to the beach. Bed load transport equations are formulated for outside and inside the surf zone. Sand transport data were collected in the field using bed load traps. Wave, tide, wind, and current information was collected simultaneously in order to verify the derived predictive equations for longshore current and sediment transport. Quite reasonable predictions are obtained for the relative distribution of bed load transport, both inside and outside the surf zone.

scholarly journals IMPROVED LONGSHORE SAND TRANSPORT EVALUATION

1988 ◽  
Vol 1 (21) ◽  
pp. 103
Author(s):  
A.S. Arcilla ◽  
A. Vidaor ◽  
J. Pous
Keyword(s):  
Sediment Transport ◽  
Dimensional Analysis ◽  
Surf Zone ◽  
Dynamic State ◽  
Sand Transport ◽  
Hydrodynamic Analysis ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Proposed Model ◽  
The One

In this paper an improved bulk formulation for the longshore sediment transport rate is presented. It is based on a simplified hydrodynamic analysis of surf zone flow and supplemented by an exhaustive dimensional analysis. The proposed model includes the effect of the surf zone dynamic state (e.g. variation of longshore sand transport, II, with breaker type) and it is now being used in the one- and twoline shoreline evolution models developed by the Maritime Engineering Laboratory in Barcelona.

scholarly journals APPLICATION OF A SEMI-EMPIRICAL LONGSHORE TRANSPORT FORMULATION

2012 ◽  
Vol 1 (33) ◽  
pp. 22
Author(s):  
Giuseppe Barbaro ◽  
Giuseppe Roberto Tomasicchio ◽  
Giovanni Malara ◽  
Felice D'Alessandro
Keyword(s):  
Sediment Transport ◽  
Transport Rate ◽  
Sediment Transport Rate ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Semi Empirical

The present paper deals with the determination of longshore sediment transport rate. Specifically, case study of Saline Joniche (Reggio Calabria, Italy, is discussed. This case is of interest because, in this location, an artificial basin was built in the 70’s. After few years, port entrance experienced total obstruction by sand. Actually, the area is abandoned and several projects have been proposed for revitalising port activities. This paper discusses a method for estimating the longshore sediment transport rate at Saline Joniche and complements previous methodology.

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