• Journal of the Korean Wood Science and Technology
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• 제45권1호
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• pp.36-42
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• 2017

본 연구는 국내 건축물의 강우에 대한 노출정도를 지역별로 평가하기 위하여 수행되었다. 바람에 의하여 벽체에 부딪치는 비를 유도강우로 표기하였으며 지역별로 유도강우의 세기를 비교하기 위하여 유도강우지수(Driving Rain Index)를 사용하였다. 국내 64개 지역에서 30년 동안 축적된 풍속과 강우량 자료를 통해서 연평균유도강우지수 (Annual Average Driving Rain Index)를 계산하였으며 이에 근거하여 측정된 지역들을 강우노출이 높은 지역, 중간 지역, 적은 지역으로 구분하였다. 측정된 지역 중 강우에 많이 노출되는 지역은 없었으며 22개 지역만이 노출정도가 중간으로 그리고 나머지 42개 지역은 강우노출정도가 낮은 것으로 평가되었다. 기후변화에 따라서 유도강우지수의 변화 폭이 큰 것으로 나타났지만 종합적으로 평가할 때 대관령, 부산, 여수 및 제주도 등의 일부 지역을 제외하면 국내 건축물의 강우노출정도는 높지 않은 것(moderate to low)으로 판단된다.

• Wind and Structures
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• 제29권4호
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• pp.279-297
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• 2019

Strong winds threaten the safety of vehicles on long-span bridges considerably, which could force traffic authorities to reduce speed limits or even close these bridges to traffic. In order to maintain the safe and economic operation of a bridge, a reasonable evaluation of the driving safety on that bridge is needed. This paper aims at carrying outdriving safety analyses for three types of vehicles on a long-span bridge in crosswinds by considering the aerodynamic interference between the bridge and the vehicles based on the wind-vehicle-bridge coupling vibration analysis. Firstly, CFD numerical simulations along with previously obtained wind tunnel testing results were used to determine the aerodynamic force coefficients of the three types of vehicles on the bridge. Secondly, the dynamic responses of the bridge and the vehicles under crosswinds were simulated, and based on those, the driving safety analyses for the three types of vehicles on the bridge were carried out for both cases considering and not considering the aerodynamic interference between the vehicles and the bridge. Finally, the effect of the aerodynamic interference on the safety of the vehicles was investigated. The results show that the aerodynamic interference between the bridge and the vehicles not only affectsthe accident critical wind speed but also the accident type for all three types of vehicles. Such effects are also different for each of the three types of vehicles being studied.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.681-687
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• 2017

본 논문은 고속철도 차량 주행풍에 기반한 풍력 발전의 가능성을 분석한다. 저자는 풍속계와 데이터 분석 프로그램을 포함한 풍속 측정 장비를 구성하였으며, 이를 활용해 실제 고속 철도 차량 노선 부근에서 주행풍의 특성을 측정하였다. 저자는 반복적인 측정을 통해 주행풍 특성의 변화를 야기할 수 있는 다양한 요인들의 영향을 고려하였다. 우선적으로, 저자는 터널의 유무 및 계곡 지형 요인에 의해 구분되는 세 지점에서 개별적으로 주행풍의 풍속 및 지속 시간을 측정하여, 지형 요인에 따른 주행풍의 특성 차이를 분석한다. 또한 세 단계에 걸쳐 높이를 점증시키며 주행풍의 특성을 측정해, 차량과의 상대적인 높이에 따른 주행풍의 변화를 분석한다. 나아가 주행 차량의 특성을 고려하여, 길이와 중량에서 차이가 있는 Korean Train eXpress (KTX) 차량과 Super Rapid Train (SRT) 차량에 따른 주행풍의 차이를 분석한다. 끝으로 측정된 주행풍의 풍속 및 지속 시간을 토대로, 실제 풍력 발전에 도입할 경우 얻을 수 있는 풍력 에너지 수준을 도출하고, 이를 통해 기대되는 효용성에 대해 논의한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.119-120
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• 2013

Wind turbines as a power distribution system linked to the driving operation according to the characteristics of the distribution system can be adversely affected by a change of circumstances, depending on Distribution Systems with driving characteristics of a wind turbine can be affected. Thus according to the grid-tied wind turbines and transient suppression of the distribution lines and distribution lines outside of the accident in order to maintain stable power supply to supply reactive power efficient system is necessary to keep the voltage constant. In this paper, we substantiated in Jeju Hangwon 12 Unit Level 1MVA STATCOM system configuration, control, configure, and test results will be introduced.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.182-189
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• 2009

The noise from the sunroof can be divided into the low frequency buffeting noise and the high frequency turbulence noise generated when a car runs at the high driving speed. The wind deflector suppresses the buffeting noise generation by accelerating the vortex shedding from the front edge of sunroof opening, and guides the flow direction so that air can pass smoothly over the sunroof opening. To reduce the buffeting noise and the high frequency noise, it is very important to locate a deflector in a proper position depending on the driving speed and the sunroof opening width. The deflector's sectional shape also plays an important role in efficiently reducing the buffeting and high frequency noise. In this paper, we determined the optimum deflector's sectional shape and examined the flow characteristics behind a sunroof deflector through CFD analysis with changing the deflector height, the driving speed and the sunroof opening width. It is found that the deflector needs to be located in the higher location to control the buffeting noise by shedding the higher frequency vortices to accelerating vortices from the sunroof front edge. The deflector may act as a new noise source at the high driving speed, then it is desirable to put the deflector at the proper height to reduce the flow fluctuations and the noise generation. We also made a road test to verify CFD analysis results in this study.

• Wind and Structures
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• 제14권1호
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• pp.71-80
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• 2011

This study presents a decision making process for installation of wind barrier which is used to reduce the wind speed applied to running vehicles on expressway. To determine whether it is needed to install wind barrier or not, cost and benefit from wind barrier are calculated during lifetime. In obtaining car accidental risk, probabilistic distribution of wind speed, daily traffic volume, mixture ratio in the volume, and duration time for wind speed range are considered. It is recommended to install wind barrier if benefit from the barrier installation exceed construction cost. In the numerical examples, case studies were shown for risk and benefit calculation and main risky regions on Korean highway were all evaluated to identify the number of installation sites.

• 한국환경과학회지
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• 제18권8호
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• pp.833-839
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• 2009

The calculation of the wind field for resource assessment is done by using CFD Reynolds-Averaged Navier-Stokes simulations performed with the commercial software WindSim. A new interface has been created to use mesoscale simulation data from a meteorological model as driving data for the simulations. This method makes it necessary to take into account thermal effects on the wind field to exploit the full potential of this method. The procedure for considering thermal effects in CFD wind field simulations as well as the impact of thermal effects on the wind field simulations is presented. Simulations for non-neutral atmospheric conditions with the developed method are consistent with expected behavior and show an improvement of simulation results compared with observations.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.78-88
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• 2018

The liberalization of electricity market and environmental concerns are the major driving forces for the development of Distributed Generation (DG). The mode of grid-connected wind power generation is becoming popular and has matured as a reliable DG technology. The voltage generated by the wind generator is stepped up to the higher voltage by the transformers before connecting to the grid. Operating algorithm of the differential relays for transformer protection used in the wind farms need to be modified to take care of the dynamic nature of fault current caused by the intermittent nature of the wind power. An algorithm for the differential relay is proposed in which dual slope characteristics are adjusted with varying fault level situation according to the wind generator in service as well as with the wind speed. A case study conducted for a typical wind farm shows that the proposed method avoids mal-operation of the differential relay in varying wind power conditions.

• 대한교통학회지
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• 제22권5호
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• pp.75-87
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• 2004

우리나라 해안지역은 강풍의 빈도가 높고 세기도 크지만 아직까지 바람을 고려한 적정속도를 안내하는 시스템은 전무한 상태이다. 강풍이 부는 곳에서의 무리한 주행은 핸들 조작의 어려움으로 인한 사고 위험과 풍속을 고려하지 않은 과속으로 인한 전복사고 등의 위험이 크다. 이러한 측면에서 바람 잦은 곳 중 주요지점에 기상정보센서(WIS:Weather Information Sensor)를 설치하고 이로부터 실시간으로 측정된 기상정보를 바탕으로 차량의 구동력과 주행저항의 크기를 극대화하는 적정속도를 VMS를 통하여 제공하는 방안이 필요하다. 목포시에 건설예정인 목포대교를 대상으로 풍속별 적정 속도를 산출한 결과, 연중 평균 풍향인 남풍일 경우 교량의 입지(정남-북)에 따라 남측으로 주행하는 차량에 대하여 풍속이 8m/h이상일 경우에는 평상시와 달리 돌풍을 대비한 여유구동력이 큰 60km/h의 속도를 안내해 주는 것이 바람직 한 것으로 나타났다. 또한 2003년도에 발생한 태풍 매미 시 목포시의 풍속인 18m/s 일 경우 시속 40km/s에서의 주행저항은 1131N으로써, 이미 변속 4단에서의 구동력(약 1054N)으로는 극복할 수 없으므로 3단 이하에서 변속을 하여야 하며, 이때의 적정속도는 주행저항과 구동력간의 차이가 가장 크게 발생하는 40km/h인 것으로 분석되었다.

• Wind and Structures
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• 제30권2호
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• pp.199-210
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• 2020

Building wind pressure coefficient transiting test is a new method to test the building wind pressure coefficient by using the wind generated by a moving vehicle, which is susceptible to natural wind and other factors. In this paper, the Commonwealth Advisory Aeronautical Research Council standard model with a scale ratio of 1:300 is used as the test object, and the wind pressure coefficient transiting test is repeated under different natural wind conditions to study the influence of natural wind. Natural wind is measured by an ultrasonic anemometer at a fixed location. All building wind pressure coefficient transiting tests meet the test conditions, and the vehicle's driving speed is 72 km/h. The mean wind pressure coefficient, the fluctuating wind pressure coefficient, and the correlation coefficient of wind pressure are used to describe the influence of natural wind on the building wind pressure coefficient transiting test qualitatively and quantitatively. Some rules, which can also help subsequent transiting tests, are also summarized.