scholarly journals Numerical Simulation of Tidal Current in Majishan Sea Area of Zhoushan Based on SCHISM

2021 ◽  
Author(s):  
Yang Tang ◽  
Qiyan Ji ◽  
Weikang Jing
Keyword(s):  
Tidal Current ◽  
High Tide ◽  
Ocean Model ◽  
Current Data ◽  
Actual Measurement ◽  
Average Flow ◽  
Flow Speeds ◽  
Tidal Changes ◽  
Triangular Elements ◽  
Sea Area

Based on the SCHISM ocean model, this paper constructs a numerical model of the Majishan sea area in Shengsi County, Zhoushan City, and numerically simulates the tidal and tidal current conditions in the sea area. The non-structural triangular elements are used to construct the high-precision nearshore terrain to accurately simulate the tidal and tidal conditions. Yearly measured tidal current data. Have a deeper understanding of the tidal currents in the Majishan sea area of Zhoushan. The results show that the Majishan sea area of Zhoushan belongs to regular shallow sea currents dominated by recurrent currents. In the actual measurement, the speed of the rising and falling tides varies, and the maximum and average flow speeds are both the high tide is greater than the medium tide and the small tide. The tidal changes are mainly controlled by the forward waves of the East China Sea, and the direction of the current is basically the same as the direction of the rising and falling tides.

scholarly journals ABRASI PANTAI DAN PENDANGKALAN KOLAM PELABUHAN JETTY PERTAMINA BALONGAN, INDRAMAYU MELALUI ANALISIS ARUS PASANG SURUT, ANGIN DAN GELOMBANG

2016 ◽  
Vol 9 (1) ◽  
pp. 15
Author(s):  
Lukman Arifin ◽  
Beben Rachmat
Keyword(s):  
Tidal Current ◽  
Current Flow ◽  
High Tide ◽  
Spring Tide ◽  
Current Data ◽  
Sediment Supply ◽  
Longshore Current ◽  
Coastal Structures ◽  
Water Based ◽  
Wave Hindcasting

Masalah utama yang terjadi di perairan sekitar kolam Pelabuhan Jetty Pertamina Balongan, Indramayu adalah abrasi dan pendangkalan. Oleh karena itu dilakukan analisis mengenai pendangkalan kolam pelabuhan dan abrasi pantai di lokasi ini dengan menggunakan data arus stasioner, trayektori arus, pasang surut dan hindcasting gelombang. Data penelitian lapangan selama satu bulan memperlihatkan telah terjadi proses pendangkalan dan abrasi pantai di sekitar area Pelabuhan Jetty Pertamina. Proses ini terjadi akibat terganggunya laju sedimen yang berasal dari selatan ke utara dan sebaliknya oleh aliran arus sejajar pantai dan arus pasang surut karena keberadaan Pelabuhan Jetty Pertamina (terganggunya kesetimbangan suplai sedimen). Kecepatan arus pasang surut pada tiga kedalaman berbeda rata-rata berkisar antara 0.168 – 0.215 m/s dan kecepatan arus terbesar sebesar 0.371 m/s terjadi pada saat spring tide. Arus pasang surut dan arus sejajar pantai secara bersinergi mempercepat terjadinya abrasi pantai dan pendangkalan kolam Pelabuhan Jetty. Laju abrasi pantai di perairan ini berdasarkan data PPPGL tahun 2003 adalah sebesar 1 – 4 m per tahun. Salah satu upaya untuk menanggulangi abrasi dan pendangkalan di kolam Pelabuhan Jetty terlebih dahulu harus di lakukan studi pemodelan. Studi pemodelan ini digunakan untuk melihat gambaran secara dinamis kondisi hidro dinamika perairan yang berhubungan dengan proses terjadinya pendangkalan dan abrasi, serta untuk menentukan tipe bangunan pantai yang sesuai. Kata kunci : pelabuhan, jetty, sedimentasi, pendangkalan, abrasi, arus, sedimen The main problem that occured around the pool of port Pertamina Jetty Balongan, Indramayu is abrasion and shoaling. Therefore an analysis of the shoaling pool of port and coastal abrasion in this location was conducted by using the stationary current data, trajectory current, tide and wave hindcasting. Data of one-month field observation shows there has been shoaling and coastal abrasion processes in the areas sorrounding port Pertamina Jetty. This process occurs due to disruption of the rate of sediment derived from south to north and vice versa by the current flow parallel to the coast and tidal current because of the presence of Pertamina Jetty port (disturbance of equilibrium sediment supply). The velocity of tidal currents on three different average depths ranging from 0.168 – 0.215 m/s and the largest flow velocity of 0.371 m/s during spring tide. The direction of static current measurement and float tracking south-southeast trending dominant at low tide and northwest-north at high tide. Tidal current and longshore current sinergies to accelerate the occurence of coastal abrasion and shoaling pool of Harbour Jetty. The rate of coastal abrasion in this water based on PPPGL data of 2003 that is 1 – 4 m/s per year. One effort to overcome abrasion and shoaling in pool Harbour Jetty should be done prior modeling studies. This modeling study is used to portraya water hydro dynamics associated with the process of shoaling and abrasion, as well as determine the appropriate types of coastal structures. Keyword : ports, jetties, sedimentation, shoaling, abrasion, currents, sediment

The Quality of Marine Water Around a Sewage Outfall

1999 ◽  
Vol 40 (7) ◽  
pp. 11-15 ◽  
Author(s):  
S. Al-Muzaini ◽  
M. Beg ◽  
K. Muslamani ◽  
M. Al-Mutairi
Keyword(s):  
Sewage Treatment ◽  
High Tide ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Coastal Region ◽  
Quality Parameters ◽  
Open Sea ◽  
Foul Smell ◽  
Sea Area ◽  
Physical And Chemical

A major sewage outlet located close to Shuwaikh Harbor discharges raw and treated water from the Al-Ardhiya sewage treatment plant, as well as raw sewage from a pumping station. It also receives input from Kuwait International Airport. The area has been spotted for its characteristic foul smell mainly because of stagnant water at the outlet. Therefore, samples were collected from eleven fixed stations at high tide and six stations at low tide to examine water quality parameters, NO3, NO2, NH3, SO4, S2, PO4, BOD, COD, TOC and heavy metals Pd, V, Cd, Ni, Mn, Cr, Cu, and total fecal coliform. The results of the physical and chemical analyses for both high-and low-tide samples along with microbiological analyses indicate that the Shuwaikh marine area is polluted. The pollution is high near the discharge point and decreases with distance. The data revealed a lower level of chemical pollutants and fecal counts at high tide than at low tide. This is mainly because of the dilution caused by incoming seawater at high tide. Although tidal movement helps reduce pollution in the area, for improvement of the situation to the desired level, biological wastewater treatment is suggested to remove most of the organic matter before discharge. Also, extension of the discharge outfall pipe to the open sea area would help reduce trapping of effluent in the coastal region and check fouling in the area.

The effects of tidal changes on the frequency of nuisance flooding events in the United States

2020 ◽  
Author(s):  
Sida Li ◽  
Thomas Wahl ◽  
David Jay ◽  
Stefan Talke ◽  
Lintao Liu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
High Tide ◽  
The United States ◽  
Tide Gauges ◽  
Relative Sea Level ◽  
Relative Sea Level Rise ◽  
Tidal Changes ◽  
Cape Fear ◽  
The U.S

<p>Nuisance flooding (NF) or high tide flooding describes minor nondestructive flooding which can nonetheless cause substantial negative socio-economic impacts to coastal communities. The frequency of NF events has increased and accelerated over the past decades along the U.S. coast, leading to changes ranging from 300% to 900%. This is mainly a result of sea level rise reducing the gap between high tidal datum and flood thresholds. While long-term relative sea level rise is the main driver for the increased number of NF events, other factors such as variability in the Gulf stream, the storm climate, and infragravity waves can also contribute. Another important driver that is often overlooked is related to changes in coastal and estuary tides, through secular trends in the amplitudes of major tidal constituents. In this presentation we assess the role of tidal changes in modulating the frequency of NF events along the U.S. coastline. We analyze hourly records from 49 U.S. tide gauges for which the National Weather Service has defined NF thresholds. We find that (1) overall across all tide gauges the number of NF days has increased since 1950 due to changes in coastal tides, adding up to 100 NF days in recent years (on top of the increase due to relative sea level rise), (2) more tide gauges experience an increase in NF events than a decrease due to changes in tides, (3) tide gauges in major estuaries which have undergone major anthropogenic alterations experience the strongest changes; in Wilmington (Cape Fear estuary), for example, 10-40% of NF events in recent years can be attributed to tidal changes. </p>

scholarly journals THREE-DIMENSIONAL SIMULATION OF TIDAL CURRENT IN LAMPUNG BAY: DIAGNOSTIC NUMERICAL EXPERIMENTS

2010 ◽  
Vol 3 (-) ◽  
Author(s):  
Alan Frendy Koropitan ◽  
Safwan Hadi ◽  
Ivonne M.Radjawane
Keyword(s):  
Tidal Current ◽  
Lower Layer ◽  
Three Dimensional ◽  
Ocean Model ◽  
Residual Current ◽  
Global Ocean ◽  
Open Boundary ◽  
Ocean Tide ◽  
Tidal Elevation ◽  
Diagnostic Mode

Princeton Ocean Model (POM) was used to calculate the tidal current in Lampung Bay using diagnostic mode. The model was forced by tidal elevation, which was given along the open boundary using a global ocean tide model-ORITIDE. The computed tidal elevation at St. 1 and St 2 are in a good agreement with the observed data, but the computed tidal current at St 1 at depth 2 m is not good and moderate approximation is showed at depth 10 m. Probably, it was influenced by non-linier effect of coastal geometry and bottom friction because of the position of current meter, mooring closed to the coastline. Generally, the calculated tidal currents in all layers show that the water flows into the bay during flood tide and goes out from the bay during ebb tide. The tidal current becomes strong when passing through the narrow passage of Pahawang Strait. The simulation of residual tidal current with particular emphasis on predominant contituent of M2 shows a strong inflow from the western part of the bay mouth, up to the central part of the bay, then the strong residual current deflects to the southeast and flows out from the eastern part of the bay mouth. This flow pattern is apparent in the upper and lower layer. The other part flows to the bay head and froms an antic lockwise circulation in the small basin region of the bay head. The anticlockwise circulations are showed in the upper layer and disappear in the layer near the bottom. Keywords: POM, diagnostic mode, tidal current, residual current, Lampung Ba.

scholarly journals NUMERICAL SIMULATIONS ON INFLUENCE OF LONG-TERM FLUCTUATION OF MEAN WATER LEVEL ON SAND WAVES IN THE KANMON WATERWAY, JAPAN

2020 ◽  
pp. 45
Author(s):  
Shiro Yamagata ◽  
Shouya Orishikise ◽  
Masaru Yamashiro ◽  
Yasuyuki Nakagawa ◽  
Noriaki Hashimoto ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Water Level ◽  
Tidal Current ◽  
Ocean Model ◽  
Spatial Difference ◽  
Sand Waves ◽  
Mean Water Level ◽  
Simulation Results ◽  
Term Fluctuation

In this study, the numerical simulation of tidal current and sediment transport in the Kanmon Waterway were performed by using a numerical simulation model FVCOM (Finite Volume Community Ocean Model (Chen et al. 2003)), in order to discuss the influence of the long-term fluctuation of mean water level on the sand waves. The numerical simulation results suggested that the spatial difference of the long-term fluctuation of mean water level in the Kanmon Straits slightly changes the tidal current around Tanoura Area, and consequently affects the development of sand waves.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kfMfIVGiLKM

Semiannual Variability of Middepth Zonal Currents along 5°N in the Eastern Indian Ocean: Characteristics and Causes

2019 ◽  
Vol 49 (10) ◽  
pp. 2715-2729 ◽  
Author(s):  
Ke Huang ◽  
Dongxiao Wang ◽  
Weiqing Han ◽  
Ming Feng ◽  
Gengxin Chen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Vertical Structure ◽  
Rossby Waves ◽  
Zonal Flow ◽  
Ocean Model ◽  
Current Data ◽  
Eastern Indian Ocean ◽  
Zonal Flows ◽  
Underlying Causes ◽  
Local Wind Forcing

AbstractFour-year (2014–17) zonal current data observed by a mooring at (5°N, 90.5°E) in the eastern Indian Ocean show a strong semiannual cycle in the middepth (~1200 m) with distinct vertical structure. This pronounced middepth semiannual variability, however, is inconsistent with the local wind forcing, which shows a predominant annual cycle. The underlying causes for this unique middepth variability along 5°N were elucidated with the addition of a reanalysis product and a continuously stratified linear ocean model. The results suggest that the observed seasonal variability in the middepth zonal flow at 5°N is primarily caused by boundary-reflected Rossby waves forced by the remote semiannual winds along the equator. Contribution from the locally wind-forced Rossby waves is much less. The theoretical Wentzel–Kramers–Brillouin ray paths further verify that the strong semiannual variability of the middepth signals over a moored region in the eastern Indian Ocean is largely a manifestation of the steep angles of propagating energy of the long Rossby waves at semiannual time scale. The annual signals are only significant in the upper and western sections (75°–80°E) as a result of the smooth trajectories of Rossby waves forced by local annual winds. Further analysis reveals that the middepth zonal currents along 5°N are expected to be associated with equatorial symmetric Rossby waves at semiannual period. Consequently, similar zonal flows should also exist in the middepth near 5°S.

scholarly journals Research on Performance Evaluation of Tidal Energy Turbine under Variable Velocity

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6313
Author(s):  
Chuhua Jiang ◽  
Xuedao Shu ◽  
Junhua Chen ◽  
Lingjie Bao ◽  
Hao Li
Keyword(s):  
Performance Evaluation ◽  
Flow Velocity ◽  
Flow Rate ◽  
Tidal Current ◽  
Evaluation System ◽  
Average Power ◽  
Tidal Energy ◽  
Time Varying ◽  
Practical Applications ◽  
Sea Area

Aiming at the performance evaluation problem of tidal energy turbines in the application of periodic time-varying flow velocity, with the goal of maximizing the efficiency of energy harvesting in practical applications, an evaluation system combining the characteristics of flow velocity changes in practical applications is proposed. After long-term monitoring of tidal current flow velocity in the applied sea area, the actual measured tidal current periodic flow velocity is divided into several flow velocity segments by using statistical segmentation, and the evaluation flow velocity of each flow velocity segment and its time proportion in the tidal current cycle are obtained. A test device with constant torque regulation is built, and capture power tests of different torque loads are carried out under each evaluation flow rate. After comparison, the maximum captured power at each evaluation flow rate is determined. We calculate the weight based on the time proportion of each evaluation flow velocity and obtain the turbine average power of the tidal cycle, thereby evaluating the overall energy capture performance of the turbine under the periodic time-varying flow velocity. Finally, the application test of the turbine in the actual sea area shows that the thin-walled airfoil turbine is more suitable for the sea area, which is the same as the pool evaluation result. The result shows that the evaluation system is reliable and effective and has significance for guiding practical engineering.

Development of a Motion Stabilizer for a Shallow-Sea-Area Spar Buoy in Wind, Tidal Current and Waves

2015 ◽  
Vol 2 (3) ◽  
pp. 182-192
Author(s):  
Toru Katayama ◽  
Kazuki Hashimoto ◽  
Hiroshi Asou ◽  
Shigenori Komori
Keyword(s):  
Tidal Current ◽  
Shallow Sea ◽  
Sea Area

scholarly journals Current Patterns in the Inner Sound (Pentland Firth) from Underway ADCP Data*

2013 ◽  
Vol 30 (1) ◽  
pp. 96-111 ◽  
Author(s):  
Lonneke Goddijn-Murphy ◽  
David K. Woolf ◽  
Matthew C. Easton
Keyword(s):  
Acoustic Doppler Current Profiler ◽  
Tidal Energy ◽  
Current Data ◽  
Northern Coast ◽  
Orkney Islands ◽  
The North ◽  
Tidal Changes ◽  
Current Profiler ◽  
Tidal Stream ◽  
Tidal Streams

AbstractNumerous acoustic Doppler current profiler (ADCP) surveys were performed in the Inner Sound of the Pentland Firth, a channel between the Orkney Islands and the northern coast of Scotland connecting the Atlantic Ocean to the west and the North Sea to the east. The Pentland Firth has the highest tidal streams of the British Isles, and one of the highest that can be found around the globe. Here, the tidal energy industry is in its demonstration phase, but not many real current measurements are in the public domain. The authors present real current data, measured during different phases of the tidal cycle, using a vessel-mounted ADCP. The tidal changes can be rapid, and because the underway measurements take time, the apparent spatial patterns are affected by temporal variation. A method is described that estimated and corrected this temporal distortion using a hydrodynamic model. It appeared that ebb and flood streams did not fully overlap, and that the tidal streams were more complicated, turbulent, and variable than existing models suggest. The data were analyzed for characteristics pertinent to practical tidal stream energy exploitation, and two favorable sites in the Inner Sound are identified. All original current data are available from the British Oceanographic Data Centre (BODC).

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