• Journal of Environmental Impact Assessment
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• v.20 no.6
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• pp.797-813
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• 2011

Frequently occurring flood and drought due to abnormal climate and global warming have increased the necessity of an effective water resources control and management of river flows. The various hydraulic structures are constructed in river as part of an effective water resources management. It is very important to analyse characteristics of flow according to installing hydraulic structures in this situations. The objective of this study is to investigate the hydraulic behaviors of flow considering affections of hydraulic structures using 2-D numerical model. To do this, both RMA-2 model and developed RAM2 model are used to analyse flow phenomena before and after installation of hydraulic structures in Nakdong river. As a result of, the water surface elevation at upstream regions increased about 22cm~66cm and the velocity around the structures sharply increased after installation of structures. The measures for the rise of water surface at upstream and local scour due to high velocity around the structures must be established when the structures is constructed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.184-193
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• 2008

The gate expansion was planed to increase discharge capacity of gate structure at sea dike in Asan Bay. So it was estimated for changing of hydraulic states in Pyeongteak Harbor Zone caused by gate expansion, using Delft3D, FLOW-3D and hydraulic physical scale model testing. In result, the influence of gate expansion was indicated to be weak.

• Journal of Korea Water Resources Association
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• v.38 no.3 s.152
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• pp.179-188
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• 2005

This study on the HwaBuk Multipurpose Dam showed that two- and three- dimensional numerical model experiments, as well as hydraulic model experiments, can be useful analysis tools for engineers. A commercially available RMA2, which solves the shallow water equations, and FLOW-3D, which solves the Reynolds averaged Navier-Stokes equations, were used to simulate the hydraulic model setup. Numerical simulation results on the following were compared with the hydraulic model results: the flow in the reservoir basin and the approaching channel; the discharge in the overflow weir; the water surface profiles in the rollway, chute, and stilling basin; and the pressure distributions in the rollway. It was shown that there is a reasonably good agreement between the numerical model and the hydraulic model for the most of computations. There were, however, some differences between the numerical simulation results and hydraulic model results for the hydraulic jump in the stilling basin because of air entrainment effect.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.471-478
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• 2012

In this study, the flow characteristic analysis at the curved-channel of the actual channel section is compared and reviewed using the 2D RMA-2 model and the 3D FLOW-3D model. the curve section with curve rate 1.044 in the research section is analyzed applying the frequency of he project flood of 100 years. According to the result, the issue for the application of the FLOW-3D Model's three-dimensional numeric analysis result to the actual river is found to be reviewed with caution. Also, application of the 3D model to the wide basin's flood characteristic is determined to be somewhat risky. But, the applicability to the hydraulic property analysis of a partial channel section and the impact analysis and forecast of hydraulic structure is presumed to be high. In addition, if the parameters to reflect the vegetation of basin and the actual channel, more accurate topological measurement data and the topological data with high closeness to the current status are provided, the result with higher reliability is considered to be drawn.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1144-1150
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• 2006

Recently, as water pollution accidents in rivers have increased, there is an increased interest in water quality forecast with accurate simulation. QUAL2E model, widely used for water quality analysis, uses the same hydraulic characteristics, such as depth and velocity, in a reach. The flow of the river is changed by various hydraulic constructions or by topography in a real river channel. In this study, a hydraulic connection module is developed to consider flow variations of river channels in QUAL2E model. The module uses the simulations results of non-uniform flow of a 1-D hydraulic model such as DWOPER or HEC-RAS. The improved QUAL2E model with this module was applied to a downstream section of Paldang Dam on the Han River. The results show the variation of water quality very well in a reach where flowing vary abruptly, like the Jamsil submerged weir.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.91-103
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• 2013

In this Research, in order to improve problems of not enough technical validation and structural and hydraulic stability evaluation when nature-friendly revetment block is applied to field, hydraulic stability evaluation according to hydraulic behavior change of porosity soil block for vegetation reinforcement that secures ecological function was reviewed. By selecting object section, numerical analysis and hydraulic model experiments were performed; for numerical analysis, by using 1-dimensional numerical analysis model HEC-RAS and 2-dimensional numerical analysis RMA-2, one-dimensional(1D) and two-dimensional(2D) numerical analysis were performed; by applying Froude's similarity law, reduced-scale hydraulic model experiments according to vegetation existence were performed. In hydraulic model experiment, for validity of experiment result, the result of velocity and tractive force of reduced-scale hydraulic model experiments was converted to prototype so that it can be compared and reviewed under the same condition of one-dimensional(1D) and two-dimensional(2D) numerical analysis result; as a result, it was confirmed that comparatively united result appeared, and by comparing prototype-converted tractive force result with revetment's allowable tractive force coming from an existing research, block's hydraulic stability was suggested.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.168-175
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• 2008

In this study, we estimated the discharge capacity of Solicheon sluice gate in Gunjang national industrial complex by hydraulic physical scale model test and FLOW-3D. It was showed that the discharge capacity of gate carried by physical model test and numerical analysis was similar.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.3
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• pp.314-321
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• 2020

In this work, a preliminary design of an inlet guide vane and runner for developing a 2.5 kW hydraulic turbine was conducted by using computational fluid dynamic analysis. Three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were used to analyze the fluid flow in the hydraulic turbine. The hexahedral grid system was used to construct computational domain, and the grid dependency test was performed to obtain the optimal grid system. Velocity triangle diagram considering the flow angles of the inlet guide vane and runner was analyzed to obtain a basic geometry of the inlet guide vane and runner. Through modification of the preliminary design, the hydraulic performances of the turbine have improved under overall drop conditions. Especially, the efficiency and power of the turbine increased by 0.95% and 1.45%, respectively, compared to those of the reference model.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.7-16
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• 2014

Vehicle industry is developing research for producing high quality injection molded product. The main objective of this study is providing information about hydraulic system for researchers who are involved in the other fields, not hydraulic field. Another objective is developing hydraulic circuit simulation model which analyzes the cause of several destabilizing elements related to quality of injection molded products. Injection molded product consists of a lot of hydraulic parts, and there are many nonlinear facts for dynamic behavior. So, we used 'SimulationX' which is specialized in hydraulic system for developing simulation model.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.707-717
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• 2013

Channel-bed of erosion and sedimentation, where eroded bed and bank materials re-deposit through the action of flow, is a natural phenomenon in alluvial systems. Analysis using a numerical model is important to understand the sediment transport mechanism associated with erosion and sedimentation near weirs and other hydraulic structures within riverine systems. The local riverbed change near a hydraulic structure (Changnyong-Haman multi-function weir in Nakdong river) has been analyzed in order to examine the effect of hydraulic structure on local bed change. A 2D numerical model (CCHE-2D) has been implemented to simulate the sedimentation and erosion over a reach (10 km) including the weir. For the calibration and verification of the model, the rainfall data from a real event (Typoon 'Maemi' in 2003) has been used for flow and stage simulation. And the simulated results show a good agreement with the observed data for whole domain. From the result, it was found that the installation and operation of weir can aggravate the local bed change caused from the flow field change and resulting redistribution of sediment.