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 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 SHOREWARD SAND TRANSPORT OUTSIDE THE SURFZONE, NORTHERN GOLD COAST, AUSTRALIA

2012 ◽  
Vol 1 (33) ◽  
pp. 26 ◽  
Author(s):  
Dean Patterson
Keyword(s):  
Surf Zone ◽  
River Mouth ◽  
Transport Processes ◽  
Gold Coast ◽  
Sand Transport ◽  
Large Wave ◽  
Wave Flume ◽  
Shoreline Evolution ◽  
The One

To date, no suitable theoretical basis has been derived to predict with reliable accuracy the shoreward sand transport under waves in the deeper water outside the surf zone. This is important for understanding the rate of recovery of beaches after major storm erosion and, in some circumstances, to quantify net shoreward supply of sand to the shoreline from the active lower shore-face below the depth of storm erosion bar development. Even a relatively low rate of long term shoreward net supply may contribute to shoreline stability where it offsets a gradient in the longshore sand transport that would otherwise lead to recession. This paper outlines the results of analysis of a 41 year dataset of beach and nearshore profile surveys to quantify annual average rates of shoreward net sand transport in 6-20m water in an area where the profiles are not in equilibrium due to the existence of a residual river mouth ebb delta bar lobe. Additionally, an empirical adaptation of the sheet flow relationship of Ribberink and Al-Salem (1990) to provide for the effects of ripples has been derived from large wave flume data and correlates well with the measured Gold Coast transport rates. These have been applied to a new coastline modelling system developed as part of research into the long term evolution of Australia’s central east coast region in response to sea level change and longshore sand transport processes, which combines the one-line concept of shoreline profile translation within the zone of littoral sand transport with cross-shore profile evolution across the deeper shore-face profile below that zone. It demonstrates the importance of providing for both the shoreward supply from the continental shelf and the varying profile response time-scale across the shore-face in predicting shoreline evolution.

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 A MODEL TO SIMULATE BEACH PROFILE EVOLUTION INDUCED BY STORMS

2018 ◽  
pp. 10
Author(s):  
Jie Zhang ◽  
Magnus Larson ◽  
Zhenpeng Ge
Keyword(s):  
Sediment Transport ◽  
Numerical Models ◽  
Model Development ◽  
High Water ◽  
Water Levels ◽  
Evolution Model ◽  
Beach Erosion ◽  
Beach Profile ◽  
Dune Erosion ◽  
Profile Change

Beach profile change induced by storms is a common and complex process in coastal engineering. Storms often bring high water levels and large waves, which erode the berm and dune, carrying large quantities of sand offshore, often causing severe damage to coastal properties. Thus, considerable research has been carried out to determine storm impact. Early studies mainly focused on laboratory investigations and analysis of field data. Since the 1980’s, many engineering numerical models of beach profile change have been developed. Kriebel and Dean (1985) proposed a model (EBEACH) to simulate the beach profile evolution with focus on dune erosion during storms, using the concept of an equilibrium beach profile (EBP). However, features such as bars and berms are not described in this model. Larson and Kraus (1989) developed an empirically based model (SBEACH) for describing the formation of bars and berms, also applying the EBP concept. Steetzel (1990) developed a model for cross-shore transport during severe storms that focuses on offshore transport and erosion. Johnson et al. (2012) developed a CS profile evolution model, CSHORE, that is mainly used to predict beach erosion under the combined effect of waves and currents. Although the model provided satisfactory performance in simulating measured berm and dune erosion in field applications, further improvements in dealing with the sediment transport in the intermittently wet-dry areas are desirable. At present, XBeach proposed by Roelvink et al. (2009) is the most popular and widely used model together with SBEACH. Although the objective of the XBeach model is to predict the profile evolution along the entire profile, i.e., both in the subaerial and subaqueous regions, the processes in the former region are less well described from a physics point of view compared to the latter. The response of the subaerial region in XBeach, including the foreshore, berm, and dune, relies on rather ad-hoc empirical sediment transport formulations. This study presents a profile evolution model that is based on the work by Larson et al. (2015). The emphasis of the model development is physically based descriptions of the subaerial profile response induced by storms. Focus of the model validation here is the berm and foreshore region.

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 A NUMERICAL MODEL OF CROSS-SHORE BEACH PROFILE EVOLUTION: THEORY, MODEL DEVELOPMENT AND APPLICABILITY

2018 ◽  
pp. 69
Author(s):  
Mohammad Tabasi ◽  
Mohsen Soltanpour ◽  
Ravindra Jayaratne ◽  
Tomoya Shibayama ◽  
Akio Okayasu
Keyword(s):  
Numerical Model ◽  
Field Data ◽  
Suspended Sediment Concentration ◽  
Surf Zone ◽  
Model Development ◽  
Sediment Concentration ◽  
Theory Model ◽  
Beach Profile ◽  
The North ◽  
North And South

A practical numerical model was developed to simulate cross-shore profile evolution at two coastal sites in Iran. The model consists of three sub-models for calculating wave and current, sediment transport, and bed level changes. Validation and calibration of the model was carried out using the measured field data on the north and south coasts of Iran, where historic measurements of cross-shore beach profiles and wave conditions have been recorded. The model is formulated for calculating cross-shore sediment transports in and outside the surf zone by the product of time-averaged suspended sediment concentration under three different mechanisms and undertow velocity. The comparisons between the model results and field data show reasonable agreement for both coastal sites and will be capable of applying it to other coastal sites with modifications to the free parameters.

scholarly journals Sulfur, Chlorine & Argon Abundances in a Southern Sample of Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 375-375
Author(s):  
Jacquelynne B. Milingo ◽  
Richard B.C. Henry ◽  
Karen B. Kwitter
Keyword(s):  
Reasonable Agreement ◽  
Massive Star ◽  
Galactic Disk ◽  
Companion Paper ◽  
Data Sets ◽  
Type Ii ◽  
Model Predictions ◽  
Abundance Trends ◽  
Homogeneous Set ◽  
Average Abundance

We present S/O, Cl/O, and Ar/O abundance ratios for 45 predominantly Type II southern PNe. These abundances are based upon line strengths from newly acquired spectrophotometry covering an extended optical range from 3600 - 9600 Å. The following average abundance ratios were obtained from this sample: S/O=0.011±0.0064, Cl/O=0.00031±0.00012, and Ar/O=0.0051±0.0020. This study, together with a sample of northern PNe, is aimed at producing a large homogeneous set of observations and abundances. Specifically, we are addressing the lack of homogeneously observed, reduced, and analyzed data sets that include the NIR [S III] lines at 9069 and 9532 Å. The data provided by these PNe samples enables us to look for consistency between S+2 abundances inferred from these lines and from the more accessible, albeit weaker, [S III] line at 6312 Å. We find reasonable agreement between S+2 determined from the NIR lines and the λ6312 line. This speaks positively for the use and reliability of the NIR lines, despite clearly recognized telluric effects in that portion of the spectrum. The consistent ionic abundance results breathe new life into our treatment of the telluric problem and the use of these strong lines for extrapolating total sulfur abundance. Type II PNe reside close to the Galactic disk and provide S, Cl, Ar, and O abundances free from nucleosynthetic self-contamination. These two qualities allow us to study massive star yields and map the distribution of these elements in radial abundance gradients. Finally, we compare our observed abundance trends with model predictions that are based on several sets of published stellar yields. (A companion paper in this volume by Kwitter & Henry discusses the northern subset observed at KPNO; see also Milingo et al. IIA, 2002, ApJS, 138, 279 and Milingo et al. IIB, 2002, ApJS, 138, 285)

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.

Experiments on Beach Profile Change with a Large Wave Flume

1982 ◽  
Author(s):  
Ryoichi Kajima ◽  
Takao Shimizu ◽  
Kohki Maruyama ◽  
Shozo Saito
Keyword(s):  
Beach Profile ◽  
Large Wave ◽  
Wave Flume ◽  
Profile Change
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