• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.354-356
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• 2015

포항항 관제구역은 2009년 8월 영일만항 개장으로 방파제(길이 5.5km) 신설에 따라 정박지 'S-5'내 조류 및 저질변화로 인해 정박선의 주묘현상이 현저하게 발생하고 있으며, 포항 신항내 고층구조물 신설로 인해 동일 시간대 풍향 풍속등 기상현상이 포항구항 및 영일만항, 호미곶과는 달리 강력하게 발생하여 입 출항선박의 안전에 위험을 초래하고 있다. 이와 같이, 관제구역내 환경변화에 따른 정박선의 현저한 주묘 및 포항 신항내 강력한 풍향 풍속등의 발생이 선박의 안전을 위협하고 있다. 본 연구에서는 관제구역내 환경변화에 따른 해상교통안전의 위험을 줄이기 위한 VTS의 역할 및 대처방안에 대해 모색해 보고자 한다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.172-174
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• 1999

이전의 연구에서는 중정도에서 강한 풍속까지의 대기경계층 난류구조는 잘 해석하였으나, 저풍속 안정한 대기조건일 때 난류구조에 대해서는 아직까지 잘 알려져 있지 않다. 또한 육지와 거대한 수계의 열적 특성차이를 갖는 임해지역에서의 확산은 Praire지역을 비롯한 내륙지역과는 다른 특성을 갖는다. 임해지역에서는 오염원으로부터 중단거리에서 저풍속시에 지표상에 고농도가 발생하는 오염물질확산현상이 잘 발생한다.(중략)

• Journal of the Korean earth science society
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• v.36 no.2
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• pp.158-170
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• 2015

This study evaluates the wind speed forecast near the surface layer using the Weather Research Forecasting with Large Eddy Simulation (WRF-LES) model in order to compare the planetary boundary layer (PBL) parameterization with the LES model in terms of different spatial resolution. A numerical simulation is conducted with 1-km and 333-m horizontal resolution over the Gangwon Province including complex mountains and coastal region. The numerical experiments with 1-km and 333-m horizontal resolution employ PBL parameterization and LES, respectively. The wind speed forecast in mountainous region shows a better forecast performance in 333-m experiment than in 1-km, while wind speed in coastal region is similar to the observation in 1-km spatial resolution experiment. Therefore, LES experiment, which directly simulates the turbulence process near the surface layer, contributes to more accurate forecast of surface wind speed in mountainous regions.

• Journal of Korean Society of Disaster and Security
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• v.6 no.2
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• pp.49-56
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• 2013

In this paper, used by the boundary layer wind tunnel test, have conducted a series of wind tunnel experiments, i.e. test the mean velocity profile regarding the surface roughness, turbulence intensity and power spectrum measured by augmentation device. After that, to provide data relevant for the preliminary design step of tall building hazard fluctuating wind loads may be obtained fluctuating pressure coefficients, fluctuating pressure spectrum, autocorrelation coefficients by the boundary layer wind tunnel test. From the results of experiments, this study can be obtained conclusions as follows. 1. We know the fact that the mean velocity profile and the turbulence intensity are well fitted natural wind flow in the boundary layer wind tunnel. 2. The satisfactory agreement of velocity spectrum can be obtained from the compare of fluctuating power spectrum and Von Karman spectrum. 3. We know the fact that the fluctuating pressure spectrums distributed peak at 0.01 Hz-0.1 Hz in the windward surfaces and at 0.1 Hz in the leeward surfaces. 4. We know the fact that the autocorrelation coefficients distributed stationary random processes with application time of hazard fluctuating wind loads.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.94-95
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• 2014

10년간(1992-2011년)의 데이터를 이용하여 태풍의 피크기에 대하여 분석하였다. 얻어진 주요 결과를 정리하면 다음과 같다. 최대풍속 20-29m/s와 40-49m/s의 태풍이 상대적으로 높은 비율을 차지하고 초강력 태풍이라고 구분할 수 있는 최대풍속 50-59m/s의 태풍도 많은 수를 차지한다. 최대풍속 50m/s 이상의 초강력 태풍은 전체 태풍 수의 24％를 차지하고 최대풍속 60m/s 이상의 태풍도 존재하여 이에 대한 항해자의 경계를 요한다. 태풍의 피크기가 주로 나타나는 곳은 북위 15도에서 25도, 동경 120도에서 140도의 해역이다. 태풍 피크기의 유지시간은 12시간 이내가 전체 태풍의 27％(59개), 13-24시간이 29％(64개), 25-48시간이 30％(66개)를 차지하여 대부분의 경우 피크기의 유지시간은 2일 이내이다. 초강력 태풍은 주로 9월에 발생하고 5월, 8월, 10월에도 높은 빈도수를 보여 이 시기에 발생하는 태풍에 대하여 각별히 주의할 필요가 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.105-110
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• 2020

This study provides a method and data for predicting the flight initiation wind speed of wind-borne debris. From the force equilibrium acting on debris including aerodynamic and inertia forces, the equation for predicting the flight initiation wind speeds are presented. Wind tunnel tests were carried out to provide necessary aerodynamic data in the equation for the debris with various aspect ratios. The proposed equation for flight initiation wind speeds was validated from free flying tests in the wind tunnel. The flights of debris were mostly initiated by slip when width to thickness was less than 10, otherwise overturning were dominant. The actual flight initiation speeds were lower than that of the computed ones. The surface boundary layer flow and the gap between the debris and surface might affect the prediction error.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.429-436
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• 2021

The wind profilers operated by the Korea Meteorological Administration observe in a low mode for intensive observation of the low levels and a high mode for intensive observation of the high levels. The LAP-3000 wind profiler installed in Bukgangneung and Changwon is characterized by the same sampling frequency of the low mode and the high mode, allowing to compare winds observed in both modes at the same altitude. As a result of analyzing the wind speed of the two points for one year in 2020, the correlation between the two modes was up to 0.2 lower than the correlation with radiosonde. The T-test for the wind speed of the two modes showed a particularly significant difference in October, where the temperature and specific humidity fluctuate frequently. The difference in the development of the atmospheric boundary layer affects the accuracy of the wind speed depending on the observation mode.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.299-303
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• 2008

• Fire Science and Engineering
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• v.31 no.4
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• pp.26-34
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• 2017

The purpose of this study is to identify and improve the performance of the adjacent room ventilation system in living room ventilation facilities, and compare and analyze the smoke control regulations of the NFPA code and the national fire safety standard (NFSC). The analysis method was fire dynamics simulation (FDS) and was used to analyze the, variations of the air supply amount, width of the boundary, change in indoor combustion and wind velocity of the incoming air. It was found to be advantageous to secure the clean layer when the amount of air supplied is less than the amount of discharged air in the fire room. However, in the supply room, it is more effective to secure the clean layer when the amount of supplied air is larger than the amount of discharged air, as a longer boundary width gives rise to better performance. In addition, it is necessary to consider the amount of air supplied and discharged as a function of the kind of flammable material. Moreover, decreasing the air inlet wind speed and amount of incoming air is advantageous for securing the clean layer of the fire room.

• Fire Science and Engineering
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• v.25 no.4
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• pp.94-102
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• 2011

Hot smoke test is done in a subway tunnel. Alcohol trays of 1.0 MW and smoke generators are used for generating hot smoke. The fans equipped with the tunnel are successively run 9 min after smoke generation. It is verified how hot smoke is controlled by fans. Velocity and direction of flow, temperature and smoke density are measured and analyzed for smoke control performance of the tunnel with fans and analyzed from the fire-safety-point of view. Velocity of smoke flow is obtained by using measured velocity and temperature at the ceiling of the tunnel. The time when smoke-control flow is builded up is different for the different positions. Velocity distributions at various positions will be used for the boundaries and the comparison data in numerical simulations for evaluation on smoke-control facilities of subway tunnel.