scholarly journals Identifikasi Distribusi Beban Sedimentasi pada Intake DAM dan Reservoir PLTA (Studi Kasus: PLTA Cirata, Purwakarta – Jawa Barat)

2020 ◽  
Vol 2 (1) ◽  
pp. 022-030
Author(s):  
Asep Irwan ◽  
Ari Wicaksono ◽  
Firda Aulia Khairin
Keyword(s):  
Calculation Method ◽  
Research Method ◽  
Flow Model ◽  
Sediment Load ◽  
River Mouth ◽  
Maximum Flow ◽  
Reservoir Operations ◽  
Simulation Results ◽  
One Year ◽  
Mike 21

Reservoirs in Indonesia are almost inseparable from the problem of sedimentation. Sedimentation issues are important in reservoir operations, including those that affect reservoir life. One of them is in the PLTA Cirata which experienced a high amount of sedimentation, based on the results of research by BPWC in 2017 the value of sedimentation was 1.96 million m3/year. The results obtained 1,565,844.51 m3 / year so that when compared with this value has a difference between 394,155.49 m3 / year, this occurs because of differences in the sedimentation calculation method. The research method uses the MIKE 21 Module (Flow Model), this research can provide information related to the sedimentation load in the PLTA Cirata. Sediment load that occurs in the intake area of the modeling results is from the Cikundul watershed with a maximum flow value in one year in 2018 of 716.14 m3/s occurred in April. As for the thickness of sediment occurs first 1-month simulation results in the location of each estuary is between 0.01 to 0.15 m for the location of the dam area of 0.01 to 0.03 m. The thickness of sediments in the Cirata area at the location of the river mouth is around ± 1.8 m / year and at the dam around ± 0:36 m / year. Types of sediment in each river mouth obtained 21.21% sand, 78.48% silt, and 0.31% gravel, for the dam area obtained 24.49% sand, 75.08% silt, and 0.43% gravel. It can be concluded that sedimentation entering the Intake area is removing sediment from each watershed namely Cikundul, Cibalagung, Cisokan, Citarum, and Cicendo.

Study on the Cyclic Loading Effects to the Railway Ballast

2013 ◽  
Vol 724-725 ◽  
pp. 1736-1739
Author(s):  
Xue Jun Wang ◽  
Bin Hua ◽  
Yi Lin Chi ◽  
Xue Yu Zhao ◽  
Fu Yu Li
Keyword(s):  
Cyclic Loading ◽  
Research Method ◽  
Flow Simulation ◽  
Railway Ballast ◽  
Compaction Rate ◽  
Simulation Process ◽  
Loading Effects ◽  
Simulation Results ◽  
Frequency Changes ◽  
Particle Flow Simulation

When ballast materials are subjected to cyclic loading, as a result, the change of particles micromechanical properties will lead to ballast degradation, permanent deformations on the railways step by step. In this paper, it presented a coupling discrete particle-flow simulation model of the railway ballast for cyclic tamping loading. Tamping frequency changes from 25HZ to 60HZ in numerical simulation process. Simulation results that the ballast compaction rate increases linearly with frequency up to a characteristic frequency 35HZ and then it declines in inverse proportion to tamping frequency. The aim of this paper is to study on the effects on the railway ballast under cyclic loading. The study shows that the discrete element method is a valid method for investigation of the microscopic properties of railway ballast now, while we have no other better research method.

scholarly journals Pengoperasian Perangkat Lunak Mike 21 Untuk Pemodelan Arus (Studi Kasus Perairan Teluk Ambon)

2015 ◽  
Vol 1 (2) ◽  
pp. 113-123
Author(s):  
Mahyaruddin Salim ◽  
Johan Risandi ◽  
Anastasia Rita Tisiana Dwi K ◽  
Candrasa Surya Dharma
Keyword(s):  
Flow Model ◽  
Mike 21

ABSTRAK Dinas Hidro Oseanografi TNI AL (Dishidros TNI AL), Lembaga Nasional yang bertugas membuat dan menerbitkan peta arus dan buku-buku pendukung navigasi lainnya, mempunyai peran yang sangat penting khususnya dalam pengumpulan data, pengolahan/pemodelan, produksi dan pendistribusian peta arus. Salah satu perangkat lunak yang digunakan oleh Dishidros TNI AL adalah perangkat lunak MIKE 21 Flow Model Hydrodynamic (HD), yang dikembangkan oleh Danish Hydraulic Institute (DHI) dengan kemampuan memodelkan arus pada suatu daerah secara 2 dimensi (2D). Tujuan penelitian ini adalah untuk mempelajari cara mengoperasikan penggunaan perangkat lunak MIKE 21, memahami proses pemodelan arus serta langkah–langkah mengatasi permasalahan yang ada didalamnya dan membuat sebuah petunjuk teknis tentang cara pemodelan arus dengan menggunakan perangkat lunak MIKE 21. Grid bathymetri menggunakan grid segi empat, dengan ukuran grid 150m x 150 m. data batimetri menggunakan data hasil digitasi peta dan data hasil survey Dishidros TNI AL tahun 2013. Elevasi pasang surut menggunakan prediksi pasut global MIKE 21. Kecepatan dan arah angin merupakan data dari NOAA. Simulasi dilakukan selama 1 bulan, 1 sampai 31 januari 2013. Berdasarkan verifikasi elevasi pasang surut prediksi Dishidros TNI AL dan hasil model diketahui bahwa adanya kesamaan fase antara prediksi Dishidros TNI AL dan hasil model. Dimana pada saat pasang kecepatan arus berkisar antara 0.0912 m/s sampai 0.0912 m/s, pada saat surut kecepatan arus berkisar antara 0.0057 m/s sampai 0.7654 m/s.

scholarly journals Optimized Spatiotemporal Data Scheduling Based on Maximum Flow for Multilevel Visualization Tasks

2020 ◽  
Vol 9 (9) ◽  
pp. 518
Author(s):  
Qing Zhu ◽  
Meite Chen ◽  
Bin Feng ◽  
Yan Zhou ◽  
Maosu Li ◽  
...  
Keyword(s):  
Flow Model ◽  
Data Flow ◽  
Scheduling Algorithm ◽  
Maximum Flow ◽  
Data Access ◽  
Spatiotemporal Data ◽  
Cloud Environment ◽  
Calculation Algorithm ◽  
Data Scheduling ◽  
First Come First Serve

Massive spatiotemporal data scheduling in a cloud environment play a significant role in real-time visualization. Existing methods focus on preloading, prefetching, multithread processing and multilevel cache collaboration, which waste hardware resources and cannot fully meet the different scheduling requirements of diversified tasks. This paper proposes an optimized spatiotemporal data scheduling method based on maximum flow for multilevel visualization tasks. First, the spatiotemporal data scheduling framework is designed based on the analysis of three levels of visualization tasks. Second, the maximum flow model is introduced to construct the spatiotemporal data scheduling topological network, and the calculation algorithm of the maximum data flow is presented in detail. Third, according to the change in the data access hotspot, the adaptive caching algorithm and maximum flow model parameter switching strategy are devised to achieve task-driven spatiotemporal data optimization scheduling. Compared with two typical methods of first come first serve (FCFS) and priority scheduling algorithm (PSA) by simulating visualization tasks at three levels, the proposed maximum flow scheduling (MFS) method has been proven to be more flexible and efficient in adjusting each spatiotemporal data flow type as needed, and the method realizes spatiotemporal data flow global optimization under limited hardware resources in the cloud environment.

A simple calculation method for estimating the flow velocity on the roof of a train running through a tunnel using an unsteady incompressible flow model

2019 ◽  
Vol 234 (7) ◽  
pp. 734-748
Author(s):  
Katsuhiro Kikuchi ◽  
Satoru Ozawa ◽  
Yuhei Noguchi ◽  
Shinya Mashimo ◽  
Takanobu Igawa
Keyword(s):  
Boundary Layer ◽  
Flow Velocity ◽  
Calculation Method ◽  
Model Experiment ◽  
Flow Model ◽  
Simple Calculation ◽  
Dimensional Model ◽  
One Dimensional ◽  
Calculation Results ◽  
Tunnel System

Predicting the aerodynamic phenomena in a train-tunnel system is important for increasing the speed of railway trains. Among these phenomena, many studies have focused on the effects of pressure; however, only a few studies have examined the effects of flow velocity. When designing train roof equipment such as a pantograph and an aerodynamic braking unit, it is necessary to estimate the flow velocity while considering the influence of the boundary layer developed on the train roof. Until now, numerical simulations using a one-dimensional model have been utilized to predict the flow velocity around a train traveling through a tunnel; however, the influence of the boundary layer cannot be taken into consideration in these simulations. For this purpose, the authors have previously proposed a simple calculation method based on a steady incompressible tunnel flow model that can take into account the influence of the boundary layer, but this method could not incorporate the unsteadiness of the flow velocity. Therefore, in this study, the authors extend the previous simple calculation method such that it can be used for an unsteady incompressible tunnel flow. The authors compare the calculation results obtained from the extended method with the results of a model experiment and a field test to confirm its effectiveness.

A Conductive Cooling Scheme for Bone Augmentation of the Proximal Femur With PMMA: An Experimental and Finite Element Study

2019 ◽  
Author(s):  
Mahsan Bakhtiarinejad ◽  
Amirhossein Farvardin ◽  
Alireza Chamani ◽  
Mehran Armand
Keyword(s):  
Finite Element ◽  
Cooling System ◽  
Peak Temperature ◽  
Curing Temperature ◽  
Maximum Temperature ◽  
Data Simulation ◽  
Cement Injection ◽  
Simulation Results ◽  
One Year ◽  
Ice Water

Abstract The rate of one-year mortality after osteoporotic hip fracture in elderly is reported to be more than 20%. Hip augmentation using polymethylmethacrylate (PMMA) is an alternative preventive approach for patients at the highest risk of osteoporotic fracture. Excessive injection volumes of PMMA however may introduce the risk of thermal osteonecrosis. We have previously proposed a Finite element (FE) simulation to estimate the bone temperature elevations after cement injection in three key locations and demonstrated an agreement between the simulation results and the temperature measurements during the experiment. Previous study showed that the maximum temperature-rise measured at the hip surface is 10°C. The aim of this study is to introduce a cooling approach to reduce the PMMA’s curing temperature after cement injection during hip augmentation. For this purpose, we perform a conductive cooling experiment with a metallic K-wire attached to an ice-water bath. We also create a finite element simulation model for the proposed cooling system to estimate the peak temperature reduction and compare the simulation results with experimental data. Simulation results demonstrate the decrease of 80% of peak curing temperature during PMMA polymerization; similarly, sawbone experiments also show that on average the peak temperature has been reduced 64% when cooling system is integrated to the hip augmentation procedure.

scholarly journals Spatial Distribution of Δ14C Values of Organic Matter in Surface Sediments Off Saru River in Northern Japan, One Year After a Flood Event in 2006

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1068-1077
Author(s):  
Seiya Nagao ◽  
Tomohisa Irino ◽  
Takafumi Aramaki ◽  
Ken Ikehara ◽  
Hajime Katayama ◽  
...  
Keyword(s):  
Organic Matter ◽  
River Mouth ◽  
Flood Event ◽  
Terrestrial Organic Matter ◽  
Sampling Area ◽  
Restricted Area ◽  
One Year ◽  
Sandy Sediments ◽  
Riverine Suspended Solids ◽  
Northern Japan

Dispersion and deposition of terrestrial organic matter by flooding on the inner shelf were studied using C/N ratios, δ13C, and Δ14C values of sedimentary organic matter. Surface sediment samples (top 2 cm) were collected from coastal areas near the Saru River in southwestern Hokkaido, northern Japan, 1 yr after a flood event in 2006. Riverine suspended solids were also collected at a fixed station downstream during 2006–2008. Sandy sediments were located at the front of the river mouth and the western part of the sampling area, with the δ13C of organic matter ranging from −23.8‰ to −22.0‰, Δ14C of –655‰ to –388‰, and an organic carbon/total nitrogen (C/N) ratio of 5.9–7.7. On the other hand, silt and clay sediments were distributed in a restricted area 11–16 km from the river mouth, with lighter δ13C (–26.7‰ to −24.1‰) and higher Δ14C (–240‰ to –77‰) of organic matter and C/N ratio (7.8–13.3). From end-member analysis, the apparently younger and less degraded organic matter in the silt and clay sediments consists mainly of terrestrial organic matter released by flood events. They remain in the depression, although most flood deposits were moved to deep-sea environments.

scholarly journals INFRAGRAVITY PERIOD OSCILLATIONS IN A CHANNEL HARBOR NEAR A RIVER MOUTH

2018 ◽  
pp. 8 ◽  
Author(s):  
Florian Bellafont ◽  
Denis Morichon ◽  
Volker Roeber ◽  
Gaël André ◽  
Stéphane Abadie
Keyword(s):  
Return Period ◽  
Pressure Sensors ◽  
River Mouth ◽  
Type Model ◽  
Storm Event ◽  
Mooring Lines ◽  
Long Period ◽  
One Year ◽  
Free Propagation ◽  
Resonance Oscillations

Port of Bayonne, located in SW France, is a channel harbor situated near the river mouth of the Adour. Long-period oscillations have repeatedly caused snapping of mooring lines of berthed ships and have led to wave resonances in an adjacent marina (seiche). To investigate mechanisms for generation of theses oscillations, a field campaign was carried out during a one-year return-period storm (Hs = 6 m and Tp = 15 s): four pressure sensors were deployed inside the port. To complement the data and to better understand the governing processes that lead to the wave transformations in Port of Bayonne, the storm event was computed with the Boussinesq-type model, BOSZ. The data confirm the model results, which show generation of long infragravity (IG) waves by the incident swell around the harbor entrance and free propagation of these waves without amplification over far distances inside Port of Bayonne. Excited by these long waves, resonance oscillations are only noticeable in a small enclosed marina. Though the IG-waves are not causing substantial changes to the water level along the harbor channel, they are suspected to excite the ships’ eigen modes, which consequently results in mooring problems.

Calculation Method for Thermal-Hydraulic System Simulation

2008 ◽  
Vol 130 (8) ◽  
Author(s):  
Li Chenggong ◽  
Jiao Zongxia
Keyword(s):  
Mathematical Models ◽  
Calculation Method ◽  
Hydraulic System ◽  
System Simulation ◽  
Cross Coupling ◽  
System Model ◽  
Lumped Parameter ◽  
Simulation Results ◽  
Simulation Time ◽  
Hydraulic System Simulation

This paper presents the fundamental approaches of modeling thermal-hydraulic component briefly. A set of lumped parameter mathematical models is developed, which are based on conservation of mass and energy. Subsequently, the connection rule for basic thermal-hydraulic components and the method to automatically generate the complete thermal-hydraulic system model are put forward. The integration methods for solving the cross-coupling thermal-hydraulic equations are also discussed for a position-controlled thermal-hydraulic system. Simulation results show the interaction between pressure and temperature. The simplified representations of thermal-hydraulic differential equations are also proposed in this paper, which can reduce simulation time. The validity of the simplified representations is judged by simulation.

scholarly journals Tidal current energy potential of Nalón river estuary assessment using a high precision flow model

2018 ◽  
Vol 8 (1) ◽  
pp. 118-123
Author(s):  
Nicolás Badano ◽  
Rodolfo Espina Valdés ◽  
Eduardo Álvarez Álvarez
Keyword(s):  
High Precision ◽  
Hydrodynamic Model ◽  
Tidal Current ◽  
Flow Model ◽  
River Estuary ◽  
River Mouth ◽  
Hydrodynamic Models ◽  
Energy Potential ◽  
Tidal Current Energy ◽  
Current Energy

Abstract Obtaining energy from tide currents in onshore locations is of great interest due to the proximity to the points of consumption. This opens the door to the feasibility of new installations based on hydrokinetic microturbines even in zones of moderate speed. In this context, the accuracy of energy predictions based on hydrodynamic models is of paramount importance. This research presents a high precision methodology based on a multidimensional hydrodynamic model that is used to study the energetic potential in estuaries. Moreover, it is able to estimate the flow variations caused by microturbine installations. The paper also shows the results obtained from the application of the methodology in a study of the Nalón river mouth (Asturias, Spain).

Establishment and Validation of a 1-D Numerical Model of Unsteady Flow and Sediment Transport in the Three Gorges Reservoir (TGR)

2013 ◽  
Vol 444-445 ◽  
pp. 901-905
Author(s):  
Ren Yong Huang ◽  
Jie Zhang
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Unsteady Flow ◽  
Calculation Method ◽  
Three Gorges Reservoir ◽  
Three Gorges ◽  
The Three Gorges ◽  
Flow And Sediment Transport ◽  
Simulation Results ◽  
Good Agreement

A numerical model for simulating unsteady flow and sediment transport in the mainstream and its tributaries at the TGR was presented in this paper, and a three-gradation method was applied to solve the flow governing equation. A experience formula was gave for the calculation of the size of groups of different coefficient of saturation recovery based on the analysis, so the traditional calculation method was improved in this paper. The validity of the model was checked with the observed data of the TGR from 2003 to 2011. Good agreement between the calculation and observed data was obtained. The simulation results show that this model could be used to simulate the flow and sediment transport at the TGR.

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