Cross-shore variation of long-term average longshore current velocity in the nearshore zone

2008 ◽  
Vol 28 (3) ◽  
pp. 491-502 ◽  
Author(s):  
Yoshiaki Kuriyama ◽  
Yoshimasa Ito ◽  
Shinichi Yanagishima
Keyword(s):  
Current Velocity ◽  
Nearshore Zone ◽  
Longshore Current

scholarly journals A GROSS LONGSHORE TRANSPORT RATE FORMULA

1972 ◽  
Vol 1 (13) ◽  
pp. 47 ◽  
Author(s):  
Cyril J. Galvin
Keyword(s):  
Current Velocity ◽  
Empirical Relation ◽  
Field Measurements ◽  
Transport Rate ◽  
Longshore Current ◽  
Physical Explanation ◽  
Littoral Drift ◽  
Longshore Transport ◽  
Term Field

Gross longshore transport rates for 11 long-term field measurements are predicted reasonably well by the empirical relation, Q=2H2, where Q is longshore transport rate in 100,000 yd3/yr, and H is a mean breaker height in feet. A physical explanation of this empirical relation assumes: (1) most littoral drift is transported in suspension; (2) longshore current velocity is predicted by V-gmTsin28j,; (3) the empirical relation is an equation for conservation of suspended sediment in the longshore current.

scholarly journals Analisa Model Matematik Arus Sejajar Pantai Pada Groin Seri Permeable

2018 ◽  
Vol 19 (2) ◽  
pp. 113
Author(s):  
Adi Surya Pria Pranata ◽  
Novi Andhi Setyo Purwono ◽  
Ary Sismiani
Keyword(s):  
Current Velocity ◽  
Physical Modeling ◽  
Surf Zone ◽  
Rip Current ◽  
Longshore Current ◽  
Long Distance ◽  
Direction Of Movement ◽  
The Mathematical Model ◽  
Additional Reduction

This research is the mathematical model has been made with two groins, permeable and impermeable groins, with the variation is in length and distance; 50 meters, 100 meters, 150 meters and 200 meters. A modelling has been done by using the data of physical modeling study by Chen., et al, 2003, and used as input to the simulation of mathematical models using 2D Boussinesq software.Results of the research showed the influence of variation model long distance between the groins, the reduction of longshore current velocity along the coast with an average 59.21% reduction for the double permeable groin with 50 meters long, 76.02% for 100 meters, 79.50% for 150 meters, 80.49% for 200 meters. The reduction of longshore current velocity along the coast are 57.42% for an impermeable groin groin double with 50 meters, 84.61% for 100 meters, 150% for 88.89 meters, and 89.91% for 200 meters. The distance variation between one groin to the other groin has a result that a longer permeable or impermeable groin affects the reduction longshore current velocity along the coast of the Surf Zone with the addition of longshore current velocity reduction occurs along the coast up to 20%. Reduction of longshore current velocity along the coast by the permeable and impermeable groin Permeable and impermeable groins has not been significantly occured in the long-term groin area exceeding Surf zone with an average additional reduction up to 5%. The longshore current velocity approaching the speed of currents along the coast for the existing conditions at a distance up to 2.4 times of length of groins. And the distance between the groins are too close if we compare to the long groins causing the current direction of movement towards the sea (rip Current). 

SALINITY BUILD-UP DUE TO BRINE DISCHARGES INTO SHALLOW COASTAL WATERS

2009 ◽  
Vol 23 (03) ◽  
pp. 541-544 ◽  
Author(s):  
DONGDONG SHAO ◽  
ADRIAN WING-KEUNG LAW
Keyword(s):  
Mathematical Model ◽  
Coastal Waters ◽  
Two Dimensional ◽  
Longshore Current ◽  
Source Condition ◽  
Continuous Point ◽  
Characteristic Features ◽  
Shallow Coastal Waters ◽  
Transient And Steady State

A two-dimensional mathematical model simulating the long-term build-up of salinity around the brine outfall is developed in this paper. A flat seabed and steady longshore current are assumed as a first step towards modelling the actual scenario. Transient and steady-state analytical solutions for continuous point source condition are derived. These solutions are then applied to assess shoreline/offshore discharge. Characteristic features such as the temporal buildup of salinity excess and the variation of the shoreline salinity with respect to time and outfall location are investigated. The effect of the advection-to-diffusion ratio ν in the modelling results is also discussed.

scholarly journals ANOTHER APPROACH TO LONGSHORE CURRENT EVALUATION

1986 ◽  
Vol 1 (20) ◽  
pp. 100
Author(s):  
M.A. Losada ◽  
A. Sanchez-Archilla ◽  
C. Vidal
Keyword(s):  
Simple Model ◽  
Predictive Model ◽  
General Expression ◽  
Current Velocity ◽  
Laboratory Data ◽  
Reynolds Stresses ◽  
Longshore Current ◽  
Current Generation ◽  
Oblique Wave ◽  
Wave Incidence

A simple model to predict the longshore current velocity at the breaker line on a beach with oblique wave incidence, is presented. The model balances driving and resistance terms (gradients of radiation and turbulent Reynolds stresses and bottom friction) to get a general expression for the velocity. This equation shows explicitely the influence of Iribarren's parameter on longshore current generation. It has been tested with field and laboratory data, obtaining a reasonable fit to measured values. The resulting (predictive) model is expected to be valid for any type of breakers though the calibration has been mainly done for spilling and plunging types, due to the scarcity of results for other breakers.

scholarly journals A FIELD STUDY OF WAVES IN THE NEARSHORE ZONE

1982 ◽  
Vol 1 (18) ◽  
pp. 3 ◽  
Author(s):  
S. Hotta ◽  
M. Mizuguchi ◽  
M. Isobe
Keyword(s):  
Field Study ◽  
Wave Height ◽  
Surf Zone ◽  
Nearshore Zone ◽  
Camera System ◽  
Joint Distributions ◽  
Initial Analysis ◽  
Sea Bottom ◽  
Initial Results

Initial results are described of precise observations of waves shoaling in the nearshore zone. The key technique of the experiments is a 16 mm memo-motion camera system by which long term measurements of waves can be made simultaneously at many locations. Six or seven pairs of synchronized cameras were mounted on a research pier crossing the surf zone. The cameras were focused on target poles mounted on sleds which were towed about 200 m outside the breaker line, and on a line of poles jetted into the sea bottom across the surf zone. Waves transforming in the nearshore zone were observed from about 400 m offshore to the shoreline. At present only the characteristics of the statistical waves, wave height distributions, wave period distributions, and the joint distributions of wave height and period are described as part of the initial analysis.

scholarly journals CONTINUOUS OBSERVATION OF LONGSHORE CURRENT VELOCITY BY USING A PENDULUM-TYPE FLOAT

2010 ◽  
Vol 66 (1) ◽  
pp. 87-92
Author(s):  
Takayuki SUZUKI ◽  
Hikari SAKAMOTO ◽  
Yoshiaki KURIYAMA
Keyword(s):  
Current Velocity ◽  
Continuous Observation ◽  
Longshore Current

scholarly journals QUANTIFYING NEARSHORE MORPHOLOGICAL RECOVERY TIME SCALES USING ARGUS VIDEO IMAGING: PALM BEACH, SYDNEY AND DUCK, NORTH CAROLINA

2012 ◽  
Vol 1 (33) ◽  
pp. 24 ◽  
Author(s):  
Roshanka Ranasinghe ◽  
Rob Holman ◽  
Matthieu De Schipper ◽  
Tom Lippmann ◽  
Jennifer Wehof ◽  
...  
Keyword(s):  
North Carolina ◽  
Time Scales ◽  
Recovery Time ◽  
Longshore Current ◽  
Physical Processes ◽  
Essential Requirement ◽  
Wave Data ◽  
Spatio Temporal ◽  
Study Sites

Time scales of post-storm nearshore morphological recovery and physical processes governing these time scales are poorly understood at present. The ability to predict nearshore morphological recovery time scales based on pre-, during- or post-resetting storm conditions is an essential requirement for building and validating scale aggregated models that operate at macro- and higher spatio-temporal scales. In this study, quality controlled ARGUS video derived beach states at Palm Beach, Sydney (4 years) and Duck, NC (2 years) and concurrent wave data are analysed to quantify the nearshore morphological recovery time scales (Tmr) and to determine the physical processes that may govern Tmr. The results show that Tmr is of the order of 5-10 days at these two beaches. Tmr is moderately positively correlated with the averaged longshore current over the 3 days immediately after the resetting storm, indicating that it might be possible to develop a predictor for Tmr based on wave conditions immediately after the resetting storm. Weak correlations are present between Tmr and several pre-storm, during-storm and post-storm parameters at the two sites. However, these correlations are inconsistent between the two sites. A thorough analysis employing long-term beach state and wave data at several different study sites is required to fully understand this phenomenon.

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