• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.593-596
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• 2008

The scour phenomenon involves the erosive potential of flowing water and the relative ability of the soil to resist erosion. The scour phenomenon in cohesive soils is much different from that in non-cohesive soils. Granular soils resist erosion by their buoyant weight and the friction between the particles. The soil particles are dislodged individually from the bed under the action of the eroding fluid. Scour in cohesive soils is much slower and more dependent on soil properties than that in non-cohesive soils. Therefore the analysis models for estimating erosion characteristics of cohesive soils should consider not only flowing water but also the relative ability of the soil to resist erosion. In this study, erosion characteristics for the clay-silt mixed soil will be analyzed as a fundamental study for development of bridge scour analysis and design system considering scour resistance capacity of a soil. For this analysis, the relationship between scour characteristics and soil properties was evaluated through scour rate test with Kaolinite samples remolded using various loading and contents of silt.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.72-74
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• 2002

In this paper, we showed the erosion characteristics of MgO protector layer releated to lifetime of plasma display panel(PDP). We observed MgO erosion characteristic as a functions of deposition conditions. In RIE condition of Xe gas, the lowest erosion rate appears in the conditions of no heating, bias voltage -30V and pressure 5mtorr. In general. as deposition rate increases, erosion rate decreases.

• Journal of Korea Water Resources Association
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• v.44 no.6
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• pp.487-495
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• 2011

The sampling and measuring methods of root fiber quantity which greatly governs the stability evaluation of a vegetated levee revetment are proposed by this study and the erosion characteristics related to root fiber quantity are analysed by the experiments. The Phragmites Japonica Steud confirmed the dominant species in a vegetated levee revetment and the Zoysinagrass are selected as the experimental vegetations. The characteristics of erosion depth and erosion rate are analysed according to the root fiber quantity and their corresponding regression equations are suggested. The erosion depth and erosion rate highly decrease with root fiber quantity by experimental results which results in great increasing the erosion resistance of a vegetated levee revetment. The corresponding regression equations for both vegetations of the Phragmites Japonica Steud and the Zoysinagrass are suggested with high determination coefficients. The erosion resistance of the Zoysinagrass is better than that of the Phragmites Japonica Steud.

• The Journal of Engineering Geology
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• v.24 no.1
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• pp.69-79
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• 2014

This study aims to elucidate the relative importance of geological characteristics, soil slope, and rainfall intensity in relation to soil erosion. To this end, indoor rainfall simulation experiments were carried out under different conditions of rainfall intensities, soil slope, and geological characteristics. The test results show that the factors affect soil erosion in the order of soil slope > rainfall intensity > organic content in the soil. Erosion rates were proportional to rainfall, and increase with increasing clay content. Therefore, the soil erosion rate increases strongly with increasing organic content and clay content. The results show that the soil erosion rate in areas of metamorphic rocks shows a marked increase compared with areas of steep slope and sedimentary rocks. These results indicate that the geological characteristics to produce soil are closely related to sedimentation before and after erosion, providing basic information for the development of models to predict soil erosion rates.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.1-9
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• 2000

The purpose of this study was to analyze the characteristics of soil erosion on the fill-slope of forest road by elapsed years after road construction. Thirteen plots were established on the fill-slope of the newly-constructed forest road, and surveyed for two years(1997~1998). In these plots, the data about soil erosion, surface runoff, vegetation coverage, slope structural characteristics and rainfall were collected. In 1997, the major causes for soil erosion were found by the correlation coefficients with the amount of surface runoff from the fill-slope, vegetation coverage, slope length, slope degree, total rainfall and max. 1 hour rainfall. But, in 1998, the major causes for soil erosion were vegetation coverage and slope degree. Using the stepwise multiple regression method, in 1997, the amount of soil erosion from the fill-slope was complexly expressed as a exponential function of statistically significant the amount of surface runoff from the fill-slope, total rainfall, slope degree of fill-slope and vegetation coverage, but, in 1998, simply expressed as a exponential function of vegetation coverage.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.150-150
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• 2021

Soil erosion due to climate change is one of the global environmental issues. Especially, Korea is vulnerable to soil erosion as the frequency of extreme rainfall events and rainfall intensity are increasing. Soil erosion causes various problems such as reduced farmlands, deterioration of water quality in rivers, etc. To these severe problems, understanding the process of soil erosion is the first process. Then, it is necessary to quantify and analyze soil ersoion using an erosion model. Soil erosion models are divided into empirical, conceptual, and physics-based models according to the structures and characteristics of models. This study used GSSHA (Gridded Surface Subsurface Hydrologic Analysis), the physics-based erosion model, running on WMS (Watershed Modeling System) to analyze soil erosion vulnerability of the CheonCheon watershed. In addition, we compared the six sediment transport capacity formulas provided in the model and evaluated the equations fir on this study site. Therefore, this result can be as a primary tool for soil conservation management.

• Journal of computational fluids engineering
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• v.16 no.2
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• pp.66-74
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• 2011

The SCR catalyst in coal-fired power plant is eroded by the collision of fly ash on the catalyst surface. However the erosion of SCR catalyst by the collision of fly ash has not been fully studied, especially in terms of fluid dynamics. Hence, in the present study, we focus on the gas and solid flows inside the SCR catalyst duct and their consequent effect on the erosion characteristics. For this purpose, computational fluid dynamics is applied to investigate the two-phase flows and to evaluate the erosion rate for different flow and particle injection conditions. Also, the erosion rate and pressure drop of commonly used square shape are compared with equilateral triangle and hexagon shapes. The pressure drop of SCR catalyst is increased when SCR catalyst surface area per unit volume increases. The erosion rate of SCR catalyst is enhanced when the particle velocity, mass flow rate of particle, particle diameter and cell density of SCR catalyst are increased. From the results, the pressure drop and erosion rate at the catalyst surface can be minimized by reducing cell density of SCR catalyst to decrease particle velocity and number of particle impacts.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.292-299
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• 2019

The hull material of a high-speed ship may cause erosion damage from fluid impact. When physical erosion and electrochemical corrosion combine, erosion corrosion damage occurs. The aluminum ship is vulnerable to erosion corrosion because it can be operated at high speed. Thus, in this study, Al5052-O and Al6061-T6 aluminum alloys for the marine environment were selected as experimental materials. The erosion corrosion resistance of Al5052-O and Al6061-T6 aluminum alloys in seawater was investigated by an erosion test and potentiodynamic polarization test at the various flow rate (0 m/s, 5 m/s, 10 m/s, 15 m/s, 20 m/s). Erosion corrosion characteristics were evaluated by surface analysis, 3D analysis, SEM analysis, and the Tafel extrapolation method. The results of surface damage analysis after the erosion test showed that Al6061-T6 presented better erosion resistance than Al5052-O. The results of the potentiodynamic polarization test at the various flow rate, corrosion current density by Tafel extrapolation presented lower values of Al6061-T6 than Al5052-O. Al5052-O showed more surface damage than Al6061-T6 at all flow rates. Consequently, Al6061-T6 presented better erosion corrosion resistance than Al5052-O. The results of this study are valuable data for selecting hull material for an aluminum alloy vessel.

• Corrosion Science and Technology
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• v.19 no.5
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• pp.239-249
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• 2020

The characteristics of cavitation-erosion damage with changes in the amplitude of 5052-O aluminum alloy for ships were investigated in a seawater environment. In the cavitation-erosion experiment, the cavitation environment was created using a vibration-generating device with a piezo-electric effect. The amplitudes of 5 ㎛, 10 ㎛, and 30 ㎛ were created by changing the geometric shape of the cavitation horn. The resistance characteristics of cavitation-erosion damage were evaluated by weight loss and pitting area. The damaged surface was analyzed using scanning electron microscopy (SEM) and 3D optical microscopy. As the amplitude increased, the amount of damage and the area of the damaged surface increased, and the damage was concentrated at the center and edge of the specimen. The pit was created after the initial incubation period with increasing experimental time, and then the pits were merged to grow and propagate into craters, and eventually, the surface was detached and damaged. The cavitation-erosion damage after 30 minutes with amplitude of 10 ㎛ and 30 ㎛ was 1.48 and 2.21 times compared to 5 ㎛, respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.695-701
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• 1999

Thermal sprayed Ni-Cr alloy coating on the carbon steel was carried out erosion-corrosion test and electrochemical corrosion test in the marine environment. THe erosion-corrosion behavior and electrochemical corrosion characteristics of substrate(SS400) and thermal sprayed Ni-Cr coating was investigated, The erosion-corrosion control efficiency of Ni-Cr coating to substrate was also estimated quantitatively.