• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.25-34
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• 2001

A grid-based KIneMatic wave soil-water EROsion and deposition Model (KIMEROM) that predicts temporal variation and spatial distribution of sediment transport in a watershed was developed. This model uses ASCII-formatted map data supported from the regular gridded map of GRASS (U.S. Army CERL, 1993)-GIS (Geographic Information Systems), and generates the distributed results by ASCIIl-formatted map data. For hydrologic process, the kinematic wave equation and Darcy equation were used to simulate surface and subsurface flow, respectively (Kim, 1798; Kim et al., 1993). For soil erosion process, the physically-based soil erosion concept by Rose and Hairsine (1988) was used to simulate soil-water erosion and deposition. The model adopts sing1e overland flowpath algorithm and simulates surface and subsurface water depth, and sediment concentration at each grid element (or a given time increment. The model was tested to a 162.3 km$^2$ watershed located in the tideland reclaimed area of South Korea. After the hydrologic calibration for two storm events in 1999, the results of sediment transport were presented for the same storm events. The results of temporal variation and spatial distribution of overland flow and sediment areas are shown using GRASS.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.375-384
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• 2020

In this study, the application of conventional cubic law to a deep depth condition was experimentally evaluated. Moreover, a modified equation for estimating the rock permeability at a deep depth was suggested using precise hydraulic tests and an effect analysis according to the vertical stress, pore water pressure and fracture roughness. The experimental apparatus which enabled the generation of high pore water pressure (< 10 MPa) and vertical stress (< 20 MPa) was manufactured, and the surface roughness of a cylindrical rock sample was quantitatively analyzed by means of 3D (three-dimensional) laser scanning. Experimental data of the injected pore water pressure and outflow rate obtained through the hydraulic test were applied to the cubic law equation, which was used to estimate the permeability of rock fracture. The rock permeability was estimated under various pressure (vertical stress and pore water pressure) and geometry (roughness) conditions. Finally, an empirical formula was proposed by considering nonlinear flow behavior; the formula can be applied to evaluations of changes of rock permeability levels in deep underground facility such as nuclear waste disposal repository with high vertical stress and pore water pressure levels.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.142-142
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• 2021

An arbitrary representation of an urban drainage sewer system was devised using a geographic information system (GIS) tool in order to calculate the surface and subsurface flow interaction for simulating urban flood. The proposed methodology is a mean to supplement the unavailability of systematized drainage system using high-resolution digital elevation(DEM) data in under-developed countries. A modified DEM was also developed to represent the flood propagation through buildings and road system from digital surface models (DSM) and barely visible streams in digital terrain models (DTM). The manhole, sewer pipe and storm drain parameters are obtained through field validation and followed the guidelines from the Plumbing law of the Philippines. The flow discharge from surface to the devised sewer pipes through the storm drains are calculated. The resulting flood simulation using the modified DEM was validated using the observed flood inundation during a rainfall event. The proposed methodology for constructing a hypothetical drainage system allows parameter adjustments such as size, elevation, location, slope, etc. which permits the flood depth prediction for variable factors the Plumbing law. The research can therefore be employed to simulate urban flood forecasts that can be utilized from traffic advisories to early warning procedures during extreme rainfall events.

• Journal of The Korean Astronomical Society
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• v.54 no.5
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• pp.157-170
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• 2021

We investigate flow and magnetic structure of a solar prominence with a focus on how the magnetic field originally determined by subsurface dynamics gives rise to the structure. We perform a magnetohydrodynamic simulation that reproduces the self-consistent evolution of a flow and the magnetic field passing freely through the solar surface. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure that is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and the magnetic field. Our results explain a diverging flow on a U-loop, a counterclockwise downdraft along a rotating field line, acceleration and deceleration of a downflow along an S-loop, and partial emergence of a W-loop, which may play key roles in determining structural properties of the prominence.

• Journal of Korea Water Resources Association
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• v.50 no.11
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• pp.795-802
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• 2017

This study shows the assessment methodology for the water resources of subsurface dams. The study area is SSangcheon subsurface dam. It is at the estuary of SSangcheon watershed forming the unconfined alluvial aquifer. there are several candidate area which are geologically similar to it at East coast. The groundwater level was computed by a 2-D FDM model, where the watershed discharge is the input as the infiltration term. The baseflow computed as the mean value of 3 watershed dischrge model is $0.5m^3/sec$. And considering the inflow near the baseflow as the dry season inflow, The groundwater level according to the change of inflow and pumping rate was computed. Specifically, Using the real pumping rate $28000m^3/day$ which is equal to the supply amount of drinking water to Sokcho city, The inflow which induce the descended groundwater level to the bottom of aquifer or the ascended groundwater level that cause the surface flow was eatimated. The simulation for increased pumping rate and additional well construction to increase the water resources, was executed. And at the extreme dry season, available pumping rate was estimated.

• Water Engineering Research
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• v.1 no.1
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• pp.25-37
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• 2000

This study presents some results of a preliminary study for the coupled precipitation and river flow prediction system. The model system in based on three numerical models, Mesoscale Atmospheric Simulation model for generating atmospheric variables. Soil-Plant-Snow model for computing interactions within soil-canopy-snow system as well as the energy and water exchange between the atmosphere and underlying surfaces, and TOPMODEL for simulating stream flow, subsurface flow, and water tabled depth in an watershed. The selected study area is the 2,703 $\alpha_4$ $\km_2$ Soyang River basin with outlet at Soyang dam site. In addition to providing the results of rainfall and stream flow predictions, some results of DEM and GIS application are presented. It is obvious that the accurate river flow predictions are highly dependant on the accurate predictation predictions.

• Journal of Ocean Engineering and Technology
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• v.7 no.1
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• pp.81-91
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• 1993

Studies on the flow pattern due to reclamation in the Myunggi-Nocksan region are carried out based on field observations and numerical experiments. Serial time series measurement of current, temperature and salinity were conducted for 1 tidal period at intervals of 1 hour from surface to bottom on station located at 128.deg. 54' 44" E, 35.deg. 01' 04" N in April and June 1992. Surface current opposite to the subsurface current causes turbulent mixing to make homogeneous salinity pattern in vertical section. Reclamation has little effect on the wave pattern and flow patterns are also nearly similar except on the nearby region of reclamation where flow speed somewhat weakened.

• Water for future
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• v.12 no.1
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• pp.56-59
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• 1979

A prompt subsurface runoff producing mechanism whih creaters a depletion curve of direct runoff hydrograph is simulated by a dead zone dispersion model technique. Runoff processes are carried out by routing of the outflow resulted from previous linear channel and effective rainfall from its corresponding subwatershed through a series of conceptual linear channels representing subwatersheds of a catchment. Working rules are explained for evaluation the model parameters such as translatory velocity, diffusive factor, and parameters concerning the infiltration and relative magnitude of the prompt subsurface flow region.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.269-272
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• 2004

The use of colloidal gas aphron (CGA), as an external oxygen carrier, provides a promising alternative to promote aerobic bioremediation of BTEX in the subsurface environment. CGA is a stable bubble supported by three surfactant layers and can supply oxygen below the soil surface uniformly due to its plug-flow characteristic. Since CGA has a hydrophobic layer that can act as a partitioning medium for hydrophobic contaminants it is known to facilitate desorption of soil-sorbed contaminants. In addition, bioaugmentation and biostimulation are possibly achieved by using CGA when generated from a solution containing BTEX-degrading microorganisms and appropriate nutrients. In this study, we presented the physico-chemical characteristics of CGA generated from a solution composed of microorganisms and nutrients. The applicability of CGA as an in situ aerobic bioremediation technology of BTEX will be further evaluated.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.592-595
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• 2011

A numerical investigation on a suction vortices, free vortices and subsurface vortices behavior in the model sump system with multi-intakes is performed A test model sump and piping system were designed based on Froude similitude for the prototype of the recommended structure layout by HI-9.B Standard for Pump Intake Design of the Hydraulic Institute. A numerical analysis of three dimensional multiphase flows through the model sump is performed by using the finite volume method of the CFX code with multi-block structured grid systems. A ${\kappa}-{\omega]$ ShearStressTransportturbulencemodelandthe Rayleigh-Plesset cavitation model are used for solving turbulence cavitating flow. From the numerical analysis, several types of vortices are reproduced and their formation, growing shedding and detailed vortex structures are investigated. To reduce abnormal vortices, an anti-vortex device is considered and its effect is investigated and discussed.