scholarly journals TIDE AND TIDAL CURRENT IN THE BALI STRAIT, INDONESIA

2015 ◽  
Vol 36 (2) ◽  
pp. 25-36 ◽  
Author(s):  
Dessy Berlianty ◽  
Tetsuo Yanagi
Keyword(s):  
Tidal Current ◽  
Ecological Model ◽  
Current Model ◽  
Spring Tide ◽  
Residual Flow ◽  
Tidal Front ◽  
Shelf Seas ◽  
Shallow Area ◽  
Tidal Constituents ◽  
Tide And Tidal Current

Tide and tidal current model of the Bali Strait in Indonesia is produced by using a Coupled Hydrodynamical-Ecological Model for Regional and Shelf Seas (COHERENS). With its resolutions in the horizontal (500meters) and the vertical (4layers), the model well reproduces the four major tidal constituents, namely M2, S2, K1, and O1 tides, and their currents. Furthermore the model is used to investigate the tide-induced residual flow and tidal front in the Bali Strait. As a results, the tide-induced residual flow in the Bali Strait during the spring tide on May 16th in 2010 can be attributed to the variation of the strength of two eddies. The first one is the clockwise circulation in the shallow area at the wide part of the strait, while the second one is the small clockwise circulation in the south of the narrow strait. On the other hand, as suggestion from Simpson and Hunter (1974), the tidal front is determined by the value of log(H/U3) (where is the water depth in meters and the amplitude oftidal current amplitude in ms-1). The front detected by the image of sea surface temperature distribution from the satellite corresponds with the contour log(H/U3) of 6.5.

scholarly journals Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area

2021 ◽  
Vol 9 (8) ◽  
pp. 912
Author(s):  
Yuezhao Tang ◽  
Yang Wang ◽  
Enjin Zhao ◽  
Jiaji Yi ◽  
Kecong Feng ◽  
...  
Keyword(s):  
Flow Field ◽  
Water Level ◽  
Tidal Current ◽  
Sea Water ◽  
High Tide ◽  
Spring Tide ◽  
River Estuary ◽  
Tidal Range ◽  
Offshore Area ◽  
Tidal Constituents

As a coastal trading city in China, Shantou has complex terrain and changeable sea conditions in its coastal waters. In order to better protect the coastal engineering and social property along the coast, based on the numerical simulation method, this paper constructed a detailed hydrodynamic model of the Shantou sea area, and the measured tide elevation and tidal current were used to verify the accuracy of the model. Based on the simulation results, the tide elevation and current in the study area were analyzed, including the flood and ebb tides of astronomical spring tide, the flood and ebb tides of astronomical neap tide, the high tide, and the low tide. In order to find the main tidal constituent types in this sea, the influence of different tidal constituents on tide elevation and tidal current in the study area was analyzed. At the same time, the storm surge model of the study area was constructed, and the flow field under Typhoon “Mangkhut” in the study area was simulated by using the real recorded data. Typhoon wind fields with different recurrence periods and intensities were constructed to simulate the change in the flow field, the sea water level, and the disaster situation along the coast. The results showed that under normal sea conditions, the sea water flows from southwest to northeast at flood tide and the flow direction is opposite at ebb tide. The tidal range is large in the northwest and small in the southeast of the study area. The tides in the study area are mainly controlled by M2, S2, K1, and O1 tidal constituents, but N2, K2, P1, and Q1 tidal constituents have significant effects on the high water level. The water level caused by typhoons increases significantly along the coast of Shantou City. In the west area of the Rong River estuary, a typhoon with a lower central pressure than 910 hPa may induce a water increase of more than 2 m.

scholarly journals HORIZONTAL DIFFUSION IN A TIDAL MODEL

1974 ◽  
Vol 1 (14) ◽  
pp. 139
Author(s):  
Haruo Higuchi ◽  
Tetsuo Yanagi
Keyword(s):  
Dimensional Analysis ◽  
Tidal Current ◽  
Hydraulic Model ◽  
Residual Flow ◽  
Tidal Model ◽  
Horizontal Diffusion ◽  
Vertical Scale ◽  
Tide And Tidal Current ◽  
Sea Area ◽  
Shallow Bay

The effect of the tidal residual flow on the horizontal diffusion in a shallow tidal bay is investigated through a hydraulic model experiment, for which Mikawa Bay in central Japan was used as a prototype. A hydraulic model of about 20 x 30 m including Mikawa Bay and neighboring sea area, with a horizontal and vertical scale of 1/2000 and 1/160 respectively, was used, and a semi-diurnal tide was provided for it. Experiments nave shown that tide and tidal current are well reproduced in the model. The tidal locus does not close, that means the existence of the residual flow. The distribution of the concentration of the dye, which is discharged from the bay bottom, corresponds to the pattern of the residual flow. The diffusion coefficient in the bay obtained through one dimensional analysis is the order of 10' cm2/sec and that through two dimensional analysis is less by one order and the dispersion coefficient becomes 105 cm2/sec. It is concluded that the dispersion due to the residual flow plays more important role on the distribution of the material in the shallow bay, as Mikawa Bay, than the diffusion due to the tidal current itself.

scholarly journals Morphodynamic Evolution of a Nourished Beach with Artificial Sandbars: Field Observations and Numerical Modeling

2021 ◽  
Vol 9 (3) ◽  
pp. 245
Author(s):  
Cuiping Kuang ◽  
Xuejian Han ◽  
Jiabo Zhang ◽  
Qingping Zou ◽  
Boling Dong
Keyword(s):  
Sediment Transport ◽  
Tidal Current ◽  
Model Simulation ◽  
Morphological Changes ◽  
Current Model ◽  
Beach Nourishment ◽  
Tidal Range ◽  
Coastal Protection ◽  
Field Observations ◽  
One Year

Beach nourishment, a common practice to replenish an eroded beach face with filling sand, has become increasingly popular as an environmentally friendly soft engineering measure to tackle coastal erosion. In this study, three 200 m long offshore submerged sandbars were placed about 200 m from the shore in August 2017 for both coastal protection and beach nourishment at Shanhai Pass, Bohai Sea, northeastern China. A series of 21 beach profiles were collected from August 2017 to July 2018 to monitor the morphological changes of the nourished beach. Field observations of wave and tide levels were conducted for one year and tidal current for 25 h, respectively. To investigate the spatial-temporal responses of hydrodynamics, sediment transport, and morphology to the presence of three artificial submerged sandbars, a two-dimensional depth-averaged (2DH) multi-fraction sediment transport and morphological model were coupled with wave and current model and implemented over a spatially varying nested grid. The model results compare well with the field observations of hydrodynamics and morphological changes. The tidal range was around 1.0 m and the waves predominately came from the south-south-east (SSE) direction in the study area. The observed and predicted beach profiles indicate that the sandbars moved onshore and the morphology experienced drastic changes immediately after the introduction of sandbars and reached an equilibrium state in about one year. The morphological change was mainly driven by waves. Under the influences of the prevailing waves and the longshore drift toward the northeast, the coastline on the leeside of the sandbars advanced seaward by 35 m maximally while the rest adjacent coastline retreated severely by 44 m maximally within August 2017–July 2018. The model results demonstrate that the three sandbars have little effect on the tidal current but attenuate the incoming wave significantly. As a result, the medium-coarse sand of sandbars is transported onshore and the background silt is mainly transported offshore and partly in the longshore direction toward the northeast. The 2- and 5-year model simulation results further indicate that shoreline salient may form behind the sandbars and protrude offshore enough to reach the sandbars, similar to the tombolo behind the breakwater.

Modelling Wave-Current-Turbulence Interactions for Tidal Energy Applications

2020 ◽  
Author(s):  
Vengatesan Venugopal ◽  
Arne Vögler
Keyword(s):  
North Atlantic ◽  
Tidal Current ◽  
Current Model ◽  
Coupled Model ◽  
Wave Model ◽  
Tidal Energy ◽  
The North ◽  
Wave Parameters ◽  
The North Atlantic ◽  
Coupled Wave

Abstract This paper presents the nature of turbulence parameters produced from 3-dimensional numerical simulations using an ocean scale wave-tidal current model applied to tidal energy sites in the Orkney waters in the United Kingdom. The MIKE 21/3 coupled wave-current model is chosen for this study. The numerical modelling study is conducted in two stages. First, a North Atlantic Ocean large-scale wave model is employed to simulate wave parameters. Spatial and temporal wind speeds extracted from the European Centre for Medium Range Weather Forecast (ECMWF) is utilised to drive the North Atlantic wave model. Secondly, the wave parameters produced from the North Atlantic model are used as boundary conditions to run a coupled wave-tidal current model. A turbulence model representing the turbulence and eddy viscosity within the coupled model is chosen and the turbulence kinetic energy (TKE) due to wave-current interactions are computed. The coupled model is calibrated with Acoustic Doppler and Current Profiler (ADCP) measurements deployed close to a tidal energy site in the Inner Sound of the Pentland Firth. The model output parameters such as the current speed, TKE, horizontal and vertical eddy viscosities, significant wave height, peak wave period and wave directions are presented, and, their characteristics are discussed in detail.

The time-varying characteristics in tidal duration asymmetry

2020 ◽  
Author(s):  
Guo Wenyun ◽  
Song Dehai ◽  
Guo Leicheng ◽  
Ge Jianzhong ◽  
Ding Pingxing ◽  
...  
Keyword(s):  
Neap Tide ◽  
Spring Tide ◽  
Time Variability ◽  
Tidal Asymmetry ◽  
Water Effect ◽  
The Changjiang Estuary ◽  
Tidal Constituents ◽  
Sea Area ◽  
Tide Interaction ◽  
Shallow Water Effect

<p>Tides always behaves different rising and falling durations, which can mostly attribute to the shallow-water effect and interactions among tidal constituents. The duration asymmetry may lead to an inequality in flood/ebb tidal current magnitudes, affecting the net sediment transport. Tidal duration asymmetry has time-dependent characteristics. We deducted a general framework for identifying the time-variability in tidal duration asymmetry. The application to the global tides showed that the fortnightly variability in tidal asymmetry is universal and that duration asymmetry can be stronger during neap tide than during spring tide. Then the framework is applied to the tides in the Changjiang Estuary. Prominent seasonal variation in tidal asymmetry is revealed, mainly relate to the river-tide interaction. Application to the tides in the Yangshan Harbor sea area revealed that the local-scale tidal asymmetry can be changed strongly by a large coastal engineering.</p>

scholarly journals Effects of Wave–Current Interaction on Storm Surge in the Pearl River Estuary: A Case Study of Super Typhoon Mangkhut

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhifa Luo ◽  
Bensheng Huang ◽  
Xiaohong Chen ◽  
Chao Tan ◽  
Jing Qiu ◽  
...  
Keyword(s):  
Storm Surge ◽  
Current Model ◽  
Spring Tide ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Wave Setup ◽  
The Pearl River Estuary ◽  
Super Typhoon ◽  
The Pearl River

This study explored the effects of interactions between waves and current on storm surge in the Pearl River Estuary (PRE) using a fully coupled wave–current model. The model was validated based on in situ observations during the traverse of super typhoon Mangkhut. The results indicated that the model could reproduce the storm surge and wave setup processes. Numerical experiments showed that simulations of storm surge are minimally affected by wave setup. The wave setup during super typhoon Mangkhut reached up to 0.23 m and contributed to the total near shore storm surge by up to 8%. The simulations of the coupled model showed a better correlation with observations compared to those of an uncoupled model. The storm surge increased with transport upstream in a tidal-dominated outlet, whereas it decreased in a river-dominated outlet. The storm surge and wave setup increased and decreased, respectively, during spring tide as compared to that during a neap tide. The storm surge increased with increasing runoff in the upper river reaches, whereas there was little change in the tidal-dominated lower river reaches. This research emphasizes the importance of integrating the effects of multiple dynamic factors in the forecasting of storm surge and provides a reference for similar studies in other estuaries with multiple outlets and a complex river network.

scholarly journals Decrease in Tide and Tidal Current in Ariake Bay

2004 ◽  
Vol 13 (4) ◽  
pp. 403-411 ◽  
Author(s):  
Takamichi Fujiwara ◽  
Yusaku Kyozuka ◽  
Takaharu Hamada
Keyword(s):  
Tidal Current ◽  
Ariake Bay ◽  
Tide And Tidal Current
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