• Geomechanics and Engineering
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• v.17 no.2
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• pp.133-143
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• 2019

An optimal hydraulic section is critical for irrigated water conservancy in seasonal frozen ground due to a large proportion of water leakage, as investigated by in-situ surveys. This is highly correlated with the frost heave of underlain soils in cold season. This paper firstly derived a practical model for frost heave of clayey soils, with temperature dependent thermal indexes incorporating phase change effect. A model test carried out on clay was used to verify the rationality of the model. A novel approach for optimizing the cross-section of irrigation canals in cold regions was suggested with live updated geometry characterized by three unique geometric constraints including slope of canal, ratio of practical flow section to the optimal and lining thickness. Allowable frost heave deformation and tensile stress in canal lining are utilized as standard in computation iterating with geometry updating while the construction cost per unit length is regarded as the eventual target in optimization. A typical section along the Jinghui irrigation canal was selected to be optimized with the above requirements satisfied. Results prove that the optimized hydraulic section exhibits smaller frost heave deformation, lower tensile stress and lower construction cost.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.465-472
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• 1999

Hydraulic model tests are performed to find economical and hdrqulically stable design of cooling water intake channel of steam power plant. The result of tests show that the standard distributiion of y-components in the chamber of CWP(circulating Water Pump) are recommended below 3.5 to maintain hydraulic stability, so that this value is considered as the design criteria. Common basin is necessary to improve the hydraulic stability of inflow, however the longer basin does not always improve the hydraulic stability , and the optimal length of basin can be found in some range. From the results the flow stability maintained the best condition when the length of basin is 7.2m. Beside the standard tests the auxiliary tests like edge , baffle, trapezoidal section and increase of pump capacity are carried out based on the optimal condition foudn in the standard tests. From the series of tests the economical and hydraulically stable design of intake channel was proposed.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1181-1190
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• 2023

Hydraulic performance and flow resistance tests were performed to confirm the main parameters of the hydraulic instrumentation that can affect the pump performance of the reactor coolant pump. The flow resistance test offers important experimental data, which are necessary to predict the behavior of the primary coolant when the circulation of the reactor coolant pump is stopped. Moreover, the shape of the hydraulic section of the pump, which was considered in the test, was prepared to compare the mixed-flow- and axial-flow-type models, the difference in the number of blades of the impeller and diffuser, the difference in the shape of the impeller blade and its thickness, and the effect of coating at the suction bell. Additionally, five models of the hydraulic part were manufactured for the experiments. In this study, the differences in performance owing to the design factors were confirmed through the experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.6
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• pp.776-781
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• 2010

Optimum design of movable hydraulic crane's booms for weight reduction was performed in this study. Since the boom weight of the present used booms is very heavy, it is needed to make them lighter structure as possible as we can. Optimum design was performed for the booms by changing from the hexagonal cross section to triangular truss structure under the conditions, which are the allowable stress for the present cross section must be maintained, and the optimized weight must be minimized. CATIAV5 was used for stress analysis and design variables were established as the height and width of the triangular truss structure. As the results, it is found that the height of the truss structure is increased in proportion to the height of the booms and the maximum stress for optimal truss structure was obtained as 412MPa, which is lower than the allowable stress for the present hexagonal cross section. The optimized weight of the booms is reduced to about 19.88% comparing to the original weight.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.95-100
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• 1999

Process intensification without any increase in bed requires the exploitation of fluid mechanical phenomena as the basis for elegant solutions to the process engineering problems which result from the need to retain and control the immobilized biomass, and for biomass recovery. The fluidized bed biological reactor provides a solution to these needs. The wastewater treatment characteristics of the fluidized bed was filled with sand media. Indirect aeration were studied experimentally. The researcher was filled with sand particle size(0.60~0.42mm) in three reactors with different section area(A)/height(H), in the state BOD loading 4.5kg-$BOD_5/m^3$ㆍd, and under the fixed state of hydraulic retention time for around 32 minutes.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.49-63
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• 2015

In this paper, the results of evaluation on the member forces in the virtual subsea tunnel lining segments and optimal thickness of the segment with changes in depth were presented. To evaluate member forces on the hypothetical subsea tunnelling cases were developed and the segmental lining member forces were calculated by performing structural analysis using the 2-Ring Beam model. Through a preliminary reinforcement design review of the cross-section using calculated member force, optimal reinforcement design was selected. Based on the results, the variations of member forces with construction conditions such as the cover depth and the hydraulic pressure are presented. In addition, optimum segment lining designs were developed for various tunnelling conditions.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.11-20
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• 2007

In this study, we reviewed the optimal space for the fishway and fish storage establishment in the section between the downstream of the Hwacheon dam and the confluence of the Pungsan river. The hydraulic stability of these facilities was also examined. In the section between the downstream of Hwacheon dam and the confluence of Pungsan river, the release flow of Hwacheon dam was set at $5,495m^3/s,\;6,110m^3/s$ and $7,537m^3/s$, and numerical simulations were executed for each instance using the HEC-RAS model and RMA-2. In the analysis of the flow velocity distributions in the subject section by release flows of Hwacheon dam, it was shown that there was over 5.0m/s of high flow velocity at Sta. $#1{\sim}Sta.$ #3, Sta. $#4{\sim}Sta.$ #6, and Sta. $#12{\sim}Sta.$ #13 of the sections analyzed in this study. The Sta. $#0{\sim}Sta.$ #1 was considered appropriate for the fishway and fish storage establishment. As seen in the results of the numerical stability review by release flow conditions of Hwacheon dam subject to the selected available areas fur fishway and fish storage, the topographically available section for the establishment of fishway and fish storage exists at Sta. $#1{\sim}Sta.$ #3 when the release flow of Hwacheon dam is $5,495m^3/s$, whereas Sta. $#0{\sim}Sta.$ #1 should be reviewed for the subject section for the establishment of fishway at release flows of $6,110m^3/s$ and $7,537m^3/s$, in addition to the figures gathered at the $5,495m^3/s$ release flow. Finally, the available section for the establishment of fishway and fish storage was determined to be Sta. $#0{\sim}Sta.$ #3. Further, if fishway and fish storage are established in the outer bank within this section, the high flow velocity section should be avoided. An alternative would be to establish for the fishway in the inner band on the section of Sta. #1 or Sta. #3.

• Tunnel and Underground Space
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• v.34 no.3
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• pp.231-247
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• 2024

In the field of high-level radioactive waste disposal targeting deep rock environments, hydraulic characteristic information serves as the most important key factor in selecting relevant disposal sites, detailed design of disposal facilities, derivation of optimal construction plans, and safety evaluation during operation. Since various rock types are mixed and distributed in a small area in Korea, it is important to conduct preliminary work to analyze the hydrogeological characteristics of rock aquifers for various rock types and compile the resulting data into a database. In this paper, we obtained hydraulic conductivity data, which is the most representative field hydraulic characteristic of a high-depth volcanic bedrock aquifer, and also analyzed and evaluated the field data. To acquire field data, we used a high-performance hydraulic testing system developed in-house and applied standardized test methods and investigation procedures. In the process of hydraulic characteristic data analysis, hydraulic conductivity values were obtained for each depth, and the pattern of groundwater flow through permeable rock joints located in the test section was also evaluated. It is expected that the series of data acquisition methods, procedures, and analysis results proposed in this report can be used to build a database of hydraulic characteristics data for high-depth rock aquifers in Korea. In addition, it is expected that it will play a role in improving technical know-how to be applied to research on hydraulic characteristic according to various bedrock types in the future.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.59-67
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• 2015

When planning for streams, adequate and definite flood control should be in the primary consideration of the planner; likewise, flood control is the basic prerequisite for the recent river restoration taking place nationwide. Planning 'safe' streams and rivers that are predictable and controllable begins from accurate survey data. In this research, we will create streams in 3D terrain models and apply them through hydraulic analysis and restoration using smart geospatial information. This process allows the extraction of more accurate data regarding streams and rivers, which makes possible precise hydraulic analysis that is superior in details to the conventional methods. The study also proposes optimal vertical section interval for efficient data processing on hydraulic analysis, applicable when LiDAR data is utilized on hydraulic analysis of urban streams. The study proposes 3D design plan and various applications for spatially planning and restoring rivers and streams.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.506-514
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• 2014

Recently the interest about the vortex intakes are rapidly increased because of its performance to drain a plenty of collected storm water at a time. The tangential intake a kind of vortex intakes is very applicable because this type is very simple and little against other types, but it has a big weakness that the vortex flow is not been rarely created below the design discharge. In this study, the characteristics of a tangential intake and two kinds of a newly suggested compound section type intake are analyzed by the 3D numerical modeling based on theories about the control shift and free drainage condition. The analysis focused on the flow condition, flow surface formation, depth-discharge relation, area ratio of air core. Based on this study, the mild-sloped compound section type intake is the optimal, but steep-sloped compound section type is also the optional for the small design discharge.