scholarly journals ONSHORE-OFFSHORE TRANSPORT AND BEACH PROFILE CHANGE

1980 ◽  
Vol 1 (17) ◽  
pp. 71 ◽  
Author(s):  
Masataro Hattori ◽  
Ryoichi Kawamata
Keyword(s):  
Gravitational Force ◽  
Surf Zone ◽  
Breaking Waves ◽  
Time Parameter ◽  
Sand Transport ◽  
Bottom Slope ◽  
Beach Profile ◽  
Physical Consideration ◽  
Offshore Transport ◽  
Profile Change

In this paper a model is presented to describe onshore-offshore sand transport in the surf zone. The model is based on the physical consideration that when the net transport attains a state of equilibrium, the power expended through gravitational force in suspending sand grains is balanced by that due to the uplifting force arising from the turbulence generated by breaking waves. Two important parameters controlling sand transport are the dimensionless fall-time parameter and bottom slope.

scholarly journals DESCRIPTION OF BEACH CHANGES USING AN EMPIRICAL PREDICTIVE MODEL OF BEACH PROFILE CHANGES

1982 ◽  
Vol 1 (18) ◽  
pp. 86 ◽  
Author(s):  
Takaaki Uda ◽  
Hiroshi Hashimoto
Keyword(s):  
Predictive Model ◽  
Sand Transport ◽  
Coastal Structures ◽  
Beach Profile ◽  
Profile Data ◽  
Longshore Transport ◽  
Profile Changes ◽  
Offshore Transport ◽  
Eigenfunction Method ◽  
Profile Change

In order to analyze beach profile changes due to longshore and onshore-offshore sand transport, here is proposed a new model named the "empirical predictive model of beach profile change", which is an application of the empirical eigenfunction method. The analysis of the profile data obtained at the Misawa fishery port in Ogawarako Coast over five years from 1973 to 1977 indicates that profile changes due to longshore transport and to onshore-offshore transport can be separated. The model is shown to be effective in the analysis of profile changes near coastal structures.

scholarly journals BEACH PROFILE CHANGE: MORPHOLOGY, TRANSPORT RATE, AND NUMERICAL SIMULATION

1988 ◽  
Vol 1 (21) ◽  
pp. 96 ◽  
Author(s):  
Magnus Larson ◽  
Nicholas C. Kraus ◽  
Tsuguo Sunamura
Keyword(s):  
Reasonable Agreement ◽  
Surf Zone ◽  
Model Development ◽  
Sand Transport ◽  
Data Sets ◽  
Beach Profile ◽  
Shape Model ◽  
Large Wave ◽  
Model Predictions ◽  
Profile Change

An empirically based engineering numerical model is presented for simulating beach profile change in the surf zone produced by waveinduced cross-shore sand transport. The model simulates the dynamics of macroscale profile change, such as the growth and movement of berms and breakpoint bars. Model development was founded on two data sets from large wave tank experiments consisting of 42 cases with different incident wave conditions, median grain size, and initial beach shape. Model predictions are tested with field data, and reasonable agreement is found.

scholarly journals EXPERIMENTS ON BEACH PROFILE CHANGE WITH A LARGE WAVE FLUME

1982 ◽  
Vol 1 (18) ◽  
pp. 85 ◽  
Author(s):  
Ryoichi Kajima ◽  
Takao Shimizu ◽  
Kohki Maruyama ◽  
Shozo Saito
Keyword(s):  
Simple Model ◽  
Transport Rate ◽  
Sand Transport ◽  
Two Dimensional ◽  
Beach Profile ◽  
Large Wave ◽  
Wave Flume ◽  
Grain Sizes ◽  
Profile Changes ◽  
Profile Change

Two-dimensional beach profile changes were investigated with a newly constructed prototype-scale wave flume. The flume is 205 m long, 3.4 m wide and 6 m deep. Sand of two grain sizes was used in the experiments. Analysis of the results was made through use of the parameter C, introduced by Sunamura and Horikawa (1974) to classify beaches as either erosional and accretionary. Beach profile changes obtained in the flume were similar to those in the prototype (field). Net sand transport rate distributions were classified into five types, two of which do not seem to have been observed in laboratory (smallscale) experiments. A simple model describing the five types was developed for evaluating two-dimensional beach profile changes.

scholarly journals MODELING COARSE SAND TRANSPORT UNDER SKEWED OSCILLATORY FLOW USING A CFD-DEM APPROACH

2018 ◽  
pp. 18
Author(s):  
Yashar Rafati ◽  
Zhen Cheng ◽  
Xiao Yu ◽  
Tian-Jian Hsu ◽  
Joseph Calantoni
Keyword(s):  
Sediment Transport ◽  
Surf Zone ◽  
Regional Scale ◽  
Breaking Waves ◽  
Coarse Sand ◽  
Sand Transport ◽  
Sheet Flow ◽  
Two Phase ◽  
Coastal Morphology ◽  
Flow Transport

Onshore/offshore sediment transport in the nearshore is an important mechanism driving the evolution of coastal morphology. The so-called sheet flow is a transport regime, in which the flow forces are intense such that a large amount of transport occurs in a concentrated layer near the bed. Onshore transport is often associated with flow skewness/asymmetry. In the nearshore zone, due to the bottom slope and wave shoaling, the wave velocity tends be onshore skewed before breaking in the surf zone. For breaking waves, the velocity asymmetry (or acceleration skewness) may also play a key role in determining net sediment transport. Understanding the net sediment transport rate in response to wave skewness/asymmetry is fundamental to a better prediction of sediment transport in regional scale morphodynamic models. In this study, we used an Euler-Lagrange two-phase model to study sheet flow transport of coarse sand under oscillatory flows subject to velocity/acceleration skewness.

scholarly journals NUMERICAL SIMULATION OF SEAWALL- BEACH PROFILE INTERACTION IN RUNUP ZONE

2017 ◽  
pp. 21
Author(s):  
Berna Ayat Aydogan ◽  
Nobuhisa Kobayashi ◽  
Yalçın Yüksel ◽  
Burak AydoÄŸan
Keyword(s):  
Numerical Model ◽  
Laboratory Tests ◽  
Surf Zone ◽  
Vertical Wall ◽  
Small Scale ◽  
Scour Depth ◽  
Beach Profile ◽  
The Cross ◽  
Run Up ◽  
Offshore Transport

This study aimed to determine beach response in the presence of a vertical wall placed in the run-up zone. The responses of natural beach and the beach with a seawall with two different configurations were studied numerically. The capability and limitation of the cross-shore numerical model CSHORE in simulating the cross-shore transformation and the beach evolution in front of a seawall situated inside the surf zone was examined. Numerical model results were compared with small scale laboratory tests (Yüksel et. al, 2014). Offshore transport was observed in all three tests and the model was shown to predict the same trends in profile evolution. Scour depth in front of the vertical wall was correctly captured by the numerical model.

scholarly journals TWO-DIMENSIONAL EMPIRICAL EIGENFUNCTION MODEL FOR THE ANALYSIS AND PREDICTION OF BEACH PROFILE CHANGES

1986 ◽  
Vol 1 (20) ◽  
pp. 87 ◽  
Author(s):  
T.W. Hsu ◽  
S.R. Liaw ◽  
S.K. Wang ◽  
S.H. Ou
Keyword(s):  
Breaking Waves ◽  
Relative Importance ◽  
Two Dimensional ◽  
Coastal Structures ◽  
Beach Profile ◽  
Radiation Stress ◽  
Profile Data ◽  
Profile Changes ◽  
D Model ◽  
Profile Change

A two-dimensional empirical eigenfunction model is proposed for the analysis and the prediction of beach profile change due to longshore and cross-shore sediment transports. Beach profile data from Redhill coast, Taiwan, measured every two months at 150 meters interval along the detached breakwaters are analyzed and the relative importance from two directions is investigated. Furthermore, by employing the method of Markov process and linear regression, a prediction model is formulated which takes into account the effect of breaking waves, bottom sediment and radiation stress of waves. This 2-D model is shown to be effective in the analysis and the prediction of beach changes near the coastal structures.

scholarly journals BEACH PROFILE CHANGE UNDER VARYING WAVE CLIMATES

1988 ◽  
Vol 1 (21) ◽  
pp. 114
Author(s):  
Yen Kai ◽  
Ren Rushu ◽  
Wang Liang
Keyword(s):  
Experimental Study ◽  
Sandy Beach ◽  
Surf Zone ◽  
Scale Effects ◽  
Characteristic Point ◽  
Beach Erosion ◽  
Two Dimensional ◽  
Regular Waves ◽  
Beach Profile ◽  
Profile Change

In the present paper results of experimental study of two-dimensional transformation of sandy beach under varying wave climates are presented. The varying wave climates were composed of different systems of regular waves exerted one after another on the model beach. Through experiments it was found that sandy beach transformation within surf zone could be expressed by the changes of characteristic point A and characteristic slope tan 13, and that although the expression for beach erosion-accretion criteria is dimensionless, similitude scale effects should still be taken into consideration.

scholarly journals NUMERICAL SIMULATION OF BEACH PROFILE CHANGES

1986 ◽  
Vol 1 (20) ◽  
pp. 106
Author(s):  
Hitoshi Nishimura ◽  
Tsuguo Sunamura
Keyword(s):  
Numerical Simulation ◽  
Surf Zone ◽  
Wave Profile ◽  
Wave Transformation ◽  
Two Dimensional ◽  
Beach Profile ◽  
Profile Changes ◽  
Wave Shoaling ◽  
Profile Change ◽  
Dimensional Wave

This paper presents an overall numerical model for predicting beach profile changes due to waves. The local rate of net on/offshore sediment transport is empirically formulated as a function of the Ursell number and Hallermeier parameter. A sub-model of two-dimensional wave transformation includes the wave shoaling, breaking and damping in a surf zone. It is combined with another sub-model of beach profile change for the analyses of wave-profile interaction. The validity of the model is examined through hindcasting of profile changes observed in ordinary and prototype-scale flumes.

scholarly journals SUSPENDED AND BEDLOAD TRANSPORT IN THE SURF ZONE: IMPLICATIONS FOR SAND TRANSPORT MODELS

2017 ◽  
pp. 30 ◽  
Author(s):  
Joep van der Zanden ◽  
Dominic A. Van der A ◽  
Tom O'Donoghue ◽  
David Hurther ◽  
Ivan Caceres ◽  
...  
Keyword(s):  
Large Scale ◽  
Surf Zone ◽  
Sediment Concentration ◽  
Breaking Waves ◽  
Bedload Transport ◽  
Transport Processes ◽  
Sand Transport ◽  
Wave Flume ◽  
Load Transport ◽  
Particle Velocities

This paper presents results obtained during a large-scale wave flume experiment focused at measuring hydrodynamics and sediment transport processes in the wave breaking region. The experiment involved monochromatic plunging breaking waves over a mobile bed barred profile consisting of D50 = 0.24 mm sand. Vertical profiles of velocity, turbulence, sand concentration and sand fluxes were measured at 12 cross-shore locations, covering the shoaling region up to the inner surf zone. Particularly high-resolution profiles were obtained near the bed within the wave bottom boundary layer, using an acoustic sediment concentration and velocity profiler (ACVP). Sheet flow concentration and particle velocities were measured at two locations near the bar crest using two conductivity-based concentration measurement tanks (CCM+). Total transport rates, obtained from the evolving bed profile measurements, were decomposed into suspended and bedload transport contributions across the bar. The present paper presents a summary of the key findings of the experiment, which are used to discuss existing approaches for modeling suspended and bed load transport in the surf zone.

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