• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.321-330
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• 2002

This study aims at the analysis of the geomorphological instantaneous unit hydrograph model (GIS-GIUH) with geographic information system for the rainfall-runoff analysis of watershed which is ungaged or doesn't have sufficient hydrologic data. The rainfall-runoff analysis was performed in Wi stream(Dongkok, Koro, Miseung, Byeungchun, Hyoreung, Museung) which is a representative experimental river basin of IHP. In the process of analysis of the GIUH model, developed GIS-GIUH model and Rosso-GIUH model were applied the study basin and computed hydrographs by these models were compared with observed hydrograph. The GiS-GIUH model shows more closely to the observed hydrograph than Rosso-GIUH model in the peak discharge of the hydrograph. For the development of the GIS-GIUH model, Gamma function factor N was given by N=3.25( $R_{B}$/ $R_{A}$)$^{0.126}$ $R_{L}$$^{-0.055}$, which is the relation of the watershed geomorphological factor, K was also obtained as K=1.50( $R_{A}$/( $R_{B}$. $R_{L}$))/$^{0.10}$.(( $L_{{\Omega}}$+ $L_{{\Omega}-1}$)/V)$^{0.37}$. As the results of analysis, it was found that GIS-GIUH model can be applied to an ungaged watersheds.eds.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.19-24
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• 2020

The interest in renewable energy is increasing due to the depletion of fossil fuels. In particular, active research on wave power, which is highly predictable and abundant, is being conducted. The coaxial accelerator-type wave power generator used in this study was designed to improve the power generation efficiency by converting bidirectional linear motion into a rotational force. In an offshore engineering basin, waves were generated, and case tests were performed according to the wave period and wave height. The experimental results were verified by the theoretical method related to the frequency response, and the overall trend was confirmed to be consistent. These results are expected to be useful in estimating the power of wave generators and designing parameters to improve the efficiency of wave energy in the design stage before manufacturing. In addition, the manufacturer can predict the wave energy efficiency of wave generators, which can reduce the development time and cost by preventing trial and error processes.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.3
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• pp.138-144
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• 2013

New experimental devices and methods to measure shaft forces of ships are proposed in this paper. The strain gauge type six-component load cell was newly designed and installed to the end of the propeller shaft. The signals generated from the sensor in the propeller rotating are transferred to the new data amplifying and processing board on the shaft and the data is transmitted to the self-made wireless receiver. To find out the characteristics of shaft forces during port and starboard turning motions in sea trial, oblique and combined yaw maneuvering tests at straight, transient, maximum yaw rate, steady conditions were performed with the model ship installed the shaft forces measuring device using circular motion tester of Samsung Ship Model Basin. Characteristics of the measured shaft forces in model tests show quantitatively good agreement with the computed values obtained by the CFD programs using the measured wake data in oblique towing conditions. In the near future, It is hoped that the estimated shaft forces for a ship from this experimental method could be validated through comparison with directly measured values of a ship.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.61-71
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• 1997

Numerical and experimental studies are carried out to analyse the resistance characteristics of a hydrofoil catamaran which is advancing on calm water with uniform speed. For the hydrofoil catamaran with modified Wigley hull which has asymmetric transverse section and transom stem, the studies are carried out for the range of Froude number 0.2 to 1.0 and the angle of attack of the hydrofoil $0.0^{\circ}$ to $3.0^{\circ}$. The model tests are carried out in the ship model basin of Inha University. Also the numerical computations using a finite difference method are performed for the simulations of fluid flow around the hull form and the results are compared with the results of the model tests. The present computation results show well quantitative agreement with the experimental results. The experimental results show that the shape and angle of attack of the foils exerts a considerable influence on the running posture and resistance performance of ship.

• Economic and Environmental Geology
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• v.49 no.5
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• pp.371-380
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• 2016

This study aims to identify the mineraloical and petrographical characteristics of caprock from drilling cores of Pohang basin as a potential $CO_2$ storage site. Experiments and modeling were conducted in order to investigate the geochemical and mineralogical caprock effects of carbon dioxide. A series of autoclave experiments were conducted to simulate the interaction in the $scCO_2$-caprock-brine using a high pressure and temperature cell at $50^{\circ}C$ and 100 bar. Geochemical and mineralogical alterations after 15 days of $scCO_2$-caprock-brine sample reactions were quantitatively examined by XRD, XRF, ICP-OES investigation. Results of mineralogical studies, together with petrographic data of caprock and data on the physicochemical parameters of brine were used for geochemical modeling. Modelling was carried out using the The Geochemist's Workbench 11.0.4 geochemical simulator. Results from XRD analysis for caprock sample showed that major compositional minerals are quartz, plagioclase, and K-feldspar, and muscovite, pyrite, siderite, calcite, kaolinite and montnorillonite were included on a small scale. Results from ICP-OES analysis for brine showed that concentration of $Ca^{2+}$, $Na^+$, $K^+$ and $Mg^{2+}$ increased due to dissolution of plagioclase, K-feldspar and muscovite. Results of modeling for the period of 100 years showed that the recrystallization of kaolinite, dawsonite and beidellite, at the expense of plagioclase and K-feldspar is characteristic. Volumes of newly precipitation minerals and minerals passing into brine were balanced, so the porosity remained nearly unchanged. Experimental and modeling results indicate the interaction between caprock and $scCO_2$ during geologic carbon sequestration can exert significant impacts in brine pH and solubility/stability of minerals.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.161-170
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• 1994

Traditional methods for the extraction of the environmental factors of waters in which environmental change is severer than in the land can not examine closely the changed phenomena because of the lack of equipments, manpower, time and cost, etc. Therefore, new practical and efficient methods are required. The research for the method to manage environment of the waters with remote sensing technology was needed. This study examined the interrelations between the data by an on-the-spot survey and Landsat TM data and presented the model for extracting factors of water quality with regression analysis and experimental formula.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.111-118
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• 2007

In order to investigate the noise characteristics of the different caviation, noise measurements were carried out in a large cavitation tunnel of the Samsuug Ship Model Basin(SSMB). The noise measurements for a 3-dimensional hydrofoil were carried out at the angle of attack of $12^{\circ}$ and $16^{\circ}$ according to the decrease in cavitation number. It is exhibited that sound pressure level(SPL) increased sharply with cavitation inception. The frequency of the noise induced by sheet cavitation was higher than that of tip vortex cavitation in the phase of cavitation inception. Within the range of the high frequency, in the case of fully developed cavitation, sheet cavitation noise was significantly increased in sound pressure level compared with tip vortex cavitation noise. In this study, the noise characteristics of the different cavitation types were considered experimentally and would be utilized as a basis for the analysis of propeller cavitation noise.

• Journal of Ocean Engineering and Technology
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• v.6 no.1
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• pp.43-51
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• 1992

The hydrodynamic performance of a floating-type OWC (Oscillating Water Column) chamber is studied numerically and experimentally in this study. The numerical approach based on two-dimensional linear theory of floating wave absorber was attempted to design an efficient wave energy absorber, while model test was performed in a wave basin to test a performance of designed model and validate the reliability of developed numerical code. The focus of study is placed mainly on the experimental study to evaluate the principal characteristics of the designed OWC chamber in regular waves. The effects of the variation of wave height on OWC device and of air pressure inside chamber are also presented. Finally, the measured results were compared with computed ones, and it was shown that the designed chamber works with high efficiency $(\eta_H>1$ over most of wave lengths covered by present study. It is therefore concluded that the developed code is capable of being successfully employed to design OWC chambers at various ocean environments, even though there exist some minor discrepancies between measured and computed results.

• Ocean and Polar Research
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• v.28 no.2
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• pp.187-199
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• 2006

The Kuroko-type seafloor massive sulfide deposits found in the western Pacific have been considered to have potentials for economic recovery of Au, Ag, Cu, Zn, and Pb. In this study, a preliminary model was developed for the technical and economic evaluation of them. The FRSC site on Lau Basin in the Tonga EEZ was selected as a target. In this study, no construction In for the metallurgical processing subsystem was accounted for. Instead, it was assumed to sell the Cu, Zn, and Pb concentrates to the existing sulfide customer smelter. The low total investment costs for the development make the venture very attractive. However, the result of the economic feasibility evaluation is still less attractive with the mean metal yield of the Kuroko on land. It is considered that commercial mining may be plausible if the richer metal yields are applied to the development. Quantitative information for metal yield is necessary for a more accurate evaluation. However, the important resource potential information regarding the amount of ore body, the inside structure, and the metal yields have not yet been clarified sufficiently. h addition, the flotation of ore body using seawater has not been tested yet. It is necessary to solve these problems through the experimental R&D and a survey.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.7
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• pp.57-66
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• 2005

The Hydrological Simulation Program - FORTRAN (HSPF) was modified to simulate nonpoint pollutant loadings from paddy fields using a field experimental data collected during 2001-2002. The concept of a 'dike height' was added in a modified HSPF code, named HSPF-Paddy, to consider the function of retaining water by a weir at the field outlet. The effect of fertilization on the variances of nutrients on the soil surface and shallow soil layer was described mathematically with a Dirac delta function (or first-order kinetics). As confirmed through model verification, the HSPF-Paddy modifications were shown to represent the function of retaining water, varied ponded water, and surface runoff by forced drain during both rainy and non-rainy seasons and reasonably predicted the water balance and nutrients behavior in paddy fields. It is a distributed watershed model which, with the paddy modifications, can now simulate nonpoint pollutant loadings where paddy fields are dominant, and it can be used to evaluate the effects of paddy fields on the water quality at a basin scale, and assess the impacts of proposed BMPs applied to paddy fields.