• Journal of Ocean Engineering and Technology
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• v.32 no.1
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• pp.21-27
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• 2018

The design and analysis of a quayside mooring system for safe mooring of Prelude FLNG under extreme environmental conditions were carried out. The design of the mooring system considered the yard operation conditions and maximum wind speed during a typhoon. In order to secure the mooring safety of Prelude FLNG under an extreme environment, a special steel structure was designed between the quay and Prelude FLNG to maintain the distance from the quay to a certain extent to avoid a collision with the inclined base. The mooring safety was also ensured by installing additional new parts on the quay. A mooring analysis and mooring safety review were performed with more rigorous modeling considering the nonlinearity of the mooring rope and fender. In order to secure additional safety of the mooring system under extreme environmental conditions, a safety assessment was conducted on the failures of the mooring components proposed in the marine mooring guidelines. Based on the results of the mooring analysis, it was confirmed that the Prelude FLNG can be safely moored even under the extreme conditions of typhoons, and a worst case scenario analysis verified that the mooring system design was robust enough. The proposed mooring analysis and design method will provide a basis for the safe mooring of ultra-large floating offshore structures of similar size in the future.

• Journal of the Korean GEO-environmental Society
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• v.10 no.2
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• pp.69-76
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• 2009

In this study, design method for debris flow and drift wood dams used in Japan was evaluated to develop currently available design method practiced in Korea. In Japan, represented a similarity in the aspects of topography and the climate compared with Korea, casualties due to debris flow, landslide, and collapse of cliff as well as earthquake, have been reported every year. Especially, debris flow had often occurred during heavy rainy season rather than due to Typhoons or localized torrential thunderstorms. Since the characteristic of the debris flow reveals in the middle of water flow and soil behaviors, the behavior of debris flow associated with drift wood was not fully understood at this moment and therefore empirical design method to design debris flow dam is adopted in the practice and currently used in Japan. Based on the result of this study, modification of debris flow design method used in Korea are presented.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.63-70
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• 2011

Livestock buildings are rural facilities as vulnerable to natural disasters as vinyl houses. Many of livestock buildings have a roof but without side walls. The roof of such structures is easily blown away by a typhoon and this results in a heavy loss. Therefore, farmers install winch curtains on the sides to prevent damages caused by typhoons. This study purposed to examine the distribution of wind pressure coefficient among different positions of livestock shed roof according to the opening of side walls. It was found that according to the distribution of peak external pressure coefficient on the roof surface of livestock shed, the wind blowing at wind angle $0^{\circ}$ was disadvantageous to roof surface regardless of the presence of side walls. However, it was confirmed that the peak external pressure coefficient was affected by wind angle and the length of eave depending on the presence of side walls.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.517-533
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• 2012

This study calculated wind speed at the height of 10 m using a disaster prediction model(Florida Public Hurricane Loss Model, FPHLM) that was developed and used in the United States. Using its distributions, a usable information of surface wind was produced for the purpose of disaster prevention when the typhoon attack. The advanced research version of the WRF (Weather Research and Forecasting) was used in this study, and two domains focusing on South Korea were determined through two-way nesting. A horizontal time series and vertical profile analysis were carried out to examine whether the model provided a resonable simulation, and the meteorological factors, including potential temperature, generally showed the similar distribution with observational data. We determined through comparison of observations that data taken at 700 hPa and used as input data to calculate wind speed at the height of 10 m for the actual terrain was suitable for the simulation. Using these results, the wind speed at the height of 10 m for the actual terrain was calculated and its distributions were shown. Thus, a stronger wind occurred in coastal areas compared to inland areas showing that coastal areas are more vulnerable to strong winds.

• Spatial Information Research
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• v.23 no.3
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• pp.79-89
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• 2015

Once the building is higher than certain size, the wind effect plays very important role in structure design. Moreover, this is more important in Korea because dangerous phenomena like typhoons are common. Rational wind resistant design is being magnified considering the global flow and climate changes. This research presented the estimation method of design wind load using spatial information analysis based on 1:5,000 digital map and performed comparative analysis with actual application cases. The wind velocity pressure exposure coefficient and topographic coefficient turned out to be more quantitative and rational when calculated through the proposed method. The time and cost are comparatively low when compared with traditional method which contribute to the economic and rational wind resistant design.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.4
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• pp.33-39
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• 2008

Typhoon Lusa in 2002 and Typhoon Maemi in 2003 caused the worst damage of landslide and debris flow to Gangwon-do. This damage includes severe damage in riverside road. The damage register indicates that this damage is concentrated on mountain areas in Gangwon-do. In recent years, the studies on GIS application to predicting landslide and debris flow have been progressing actively. Landslide risk map managed by The Forest Service is the representative one. In this study, we generated landslide and debris flow hazard maps using statistical analysis and deterministic analysis in Gangnung area where Typhoons caused severe damage to riverside roads. We built damage point GIS DB from damage registers of National Road Maintenance Agency and field survey, and verified accuracy of landslide and debris flow hazard maps using GIS methods.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.58-64
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• 2020

Large-scale flooding due to extreme weather and typhoons causes heavy damage. This is especially true in urban areas where accumulated debris prevents the smooth drainage of rainwater in sewage facilities such as rain gutters installed near roads. In this study, to improve the drainage performance and effectively remove foreign substances by applying the dust screen used in rivers, the rain gutter with Coanda effect was simulated and compared with the experiment. The simulation was performed by setting the parameters to the fillet radius R₁ and R₂ at the top of the screen filter, the fillet radius R₃ at the bottom of the screen filter, and the height H of the gap W from the bottom. W is the gap at the backside of screen filter which is applied to stimulate the Coanda effect. According to the simulation results, the highest drain performance was 87.99% derived from R₁= 30mm, R₂= 5mm, R₃= 85mm, H= 75mm, and W= 2mm. The error rate of simulation results refer to the 4.89%~7.36% compared to the experimental results. In the future, by considering the slope according to the installation environment, the simulation results can be applied to the actual roadside to help prevent flood damage.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.100-107
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• 2002

The sea-surface winds during the passage of 64 typhoons for 1979-1999 were simulated using two different typhoon wind models, ie, typhoon parametric model(TPM) and primitive vortex model(PVM). The model hindcast winds were compared with the winds observed at JMA ocean buoys(22001 and 21002) and Kyushu ocean observation tower. The analysis of ms and relative errors between hindcast and observed winds was made to find the accuracy and sensitivity of the typhoon wind prediction models. Both hindcast winds of TPM and PVM underestimate the observed typhoon winds, but PVM winds are more closer to the observations with less rms and relative errors. Relative errors of two model winds were small within 200km from typhoon center, but TPM's relative errors increase up to 70% as the radial distance from typhoon center increases beyond > 200km although PVM's relative errors remain in 20% with less sensitive to the distance from typhoon centers.

• Journal of Korean Society of Disaster and Security
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• v.8 no.1
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• pp.39-46
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• 2015

This study is concerned with the estimation of fluctuation wind velocity spectrum and turbulence characteristics in the major cities reflecting the recent meteorological with typhoon wind velocity about 2003 (Maemi) 2010 (Kompasu) 2012 (Tembin). The purpose of this paper is to present spectral analysis for longitudinal component fluctuating velocity obtained by Monte Carlo Simulation method. In the processes of analysis, the longitudinal velocity spectrums are compared widely used spectrum models with horizontal wind velocity observations data obtained at Korea Meteorological Adminstration (KMA) and properties of the atmospheric air for typhoon fluctuating wind data are estimated to parameters with turbulency intensity, shear velocity, probability distribution and roughness length.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1415-1425
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• 2017

Typhoons are accompanied by strong wind and heavy rains. It causes casualties and property damage on the Korean peninsula every year. The effect of typhoon to daily precipitation should be quantified to prevent the damage of typhoon. Daily precipitation, maximum wind speed and, mean wind speed data was collected from 60 weather stations between 1976 and 2016. The parameters of the generalized extreme value distribution were estimated through the maximum likelihood estimation and the L-moment estimation. The impact of a typhoon can be obtained through a comparison of return levels between the whole data and typhoon excluded data. We conclude that the eastern and southern coastline are exposed to the risk of heavy rainfall which is caused by typhoon.