• Wind and Structures
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• 제17권4호
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• pp.419-433
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• 2013

This paper investigates the vertical profiles of horizontal mean wind speed and direction based on the synchronized measurements from a Doppler radar profiler and an anemometer during 16 tropical cyclones at a coastal site in Hong Kong. The speed profiles with both open sea and hilly exposures were found to follow the log-law below a height of 500 m. Above this height, there was an additional wind speed shear in the profile for hilly upwind terrain. The fitting parameters with both the power-law and the log-law varied with wind strength. The direction profiles were also sensitive to local terrain setups and surrounding topographic features. For a uniform open sea terrain, wind direction veered logarithmically with height from the surface level up to the free atmospheric altitude of about 1200 m. The accumulated veering angle within the whole boundary layer was observed to be $30^{\circ}$. Mean wind direction under other terrain conditions also increased logarithmically with height above 500 m with a trend of rougher exposures corresponding to lager veering angles. A number of empirical parameters for engineering applications were presented, including the speed adjustment factors, power exponents of speed profiles, and veering angle, etc. The objective of this study aims to provide useful information on boundary layer wind characteristics for wind-resistant design of high-rise structures in coastal areas.

• 한국환경과학회지
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• 제10권3호
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• pp.187-194
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• 2001

For the purpose of predicting air pollutants concentration in Pusan coastal urban, we used an Eulerian model of flow and dispersion/chemistry/deposition process considering SST effects which estimate through POM. The results of air quality model including emission from various sources show that the seasonal variation pattern of respective pollutants was affected by the seasonal SST fields and local circulation. Horizontal deviation of diurnal SST was 2.5~4K, especially large gradients in coastal region. Through numerical simulation of wind fields we predicted that local circulation prevailed during daytime in summer and nighttime in winter. So high concentration distribution showed toward inland in spring and summer seasons, while high concentration distribution showed at inland near coast in autumn and winter.

• 대한지리학회지
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• 제47권3호
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• pp.390-406
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• 2012

제주도 돌담은 최근 들어 문화유적, 관광자원 등으로 주목받으며 지방자치단체 차원에서 다양한 복원사업이 추진되고 있다. 본 연구는 돌담의 물리적인 복원과 함께 돌담의 형성 배경과 의미를 밝히는 것 역시 중요한 일이라 생각되어 진행하였다. 집주변에 울타리를 형성하고 있는 돌담인 울담의 높이를 중심으로 조사를 하였고 바람지도, 지질도, 주민 인터뷰를 활용하여 연구를 하였다. 연구결과, 제주도 해안마을에서는 돌을 쉽게 구할 수 있고, 주민들이 방풍 역할을 주목적 기능으로 울담을 세운 마을의 경우에 최대 풍속이 큰 곳에서 울담이 높게 나타나는 경향이 있다는 것을 확인할 수 있었다.

• 한국수산과학회지
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• 제22권2호
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• pp.79-85
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• 1989

대륙붕과 대륙사면을 갖는 직사각형 해양의 북쪽 일부분에서 불어오는 바람에 대한 이 해양의 초기 단계에서의 반응이 수치실험을 통하여 관찰되었으며 그 결과는 다음과 같다. 1. 전반적으로 보아 대륙붕파와 아주 유사한 파동이 발생되었으며 대륙붕을 따라 반시계방향으로 전파되었다. 2. 가장 먼저 대륙사면 밖에 중심을 두는 반시계방향의 vortex가 서쪽해안에 발생하여 해안을 따라 반시계방향으로 전파하며 그 속도는 $200\~300km/day$이다. 3. 바람응력이 끝날 즈음부터 대륙사면에 중심을 두는 일련의 vortex들이 생기나 해안을 따라 전파하며, 이 vortex들은 이 모델해양의 고유 모드중의 하나와 관련되는 것으로 생각된다. 4. 초기 단계에서의 대륙붕파의 발생은 각 모드별로 시차를 갖고 선택적으로 발달되어 전파되는 것으로 보여진다.

• 전기학회논문지
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• 제58권7호
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• pp.1356-1362
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• 2009

IEC 61400-25(Communications for monitoring and control of wind power plants) is established as a international standard by IEC TC 88 in 2007 with the growth of the wind power industry. In this paper, MMS service which is defined in lEC 61400-25 part 4 is implemented, and the wind power generator is objectified by using the VMD of MMS service. We also implemented MMS communication system between the wind power generator and the local control center using the proposed VMD. The performance of the developed MMS communication system is verified through the XML based user interface on the web browser.

• Wind and Structures
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• 제31권1호
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• pp.1-14
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• 2020

This paper presents a method of estimation of fatigue demands on connection bolts of tubular steel wind turbine towers. The presented method relies on numerical simulation of aerodynamic loads and structural behavior of bolted connections modeled using finite element method. Variability of wind parameters is represented by a set of values derived from their probability densities, which are adjusted based on field measurements. Numerically generated stress time-series show agreement with the measurements from strain gauges inside bolts, in terms of power spectra and the resulting damage. Position of each bolt has a determining effect on its fatigue damage. The proposed framework for fatigue life estimation represents the complexities in loading and local behavior of the structure. On the other hand, the developed procedure is computationally efficient since it requires a limited number of simulations for statistically representing the wind variations.

• 한국조경학회지
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• 제31권3호
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• pp.58-73
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• 2003

It is well known that urban environment affects climate, as we can see in the quality of bio-climate. However, climate has not been recognised properly in the urban planning process. The role it flays needs to be examined for better urban environment. The main objective of this study is to investigate the climate-ecological priority area which produces cold fresh air and thermal induced wind circulation between rural and urban areas. The objective is also to improve the quality of bio-climate and wind circulation at blocked urban areas. This paper uses the measurement and analysis method of wind direction and wind speed in order to investigate the climate-ecological priority area and cold fresh air corridor. In this study, local climate conditions i.e. wind speed, wind direction, temperature, humidity etc., were measured at nine fields and analyzed. On the basis of the climate measurement, the climate ecological priority areas were delineated; These will be assigned as climate-ecological conservation areas.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.315-327
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• 2016

Background: This study evaluated the atmospheric dispersion of radioactive material according to local weather conditions and emission conditions. Materials and Methods: Local weather conditions were defined as 8 patterns that frequently occur around the Kori Nuclear Power Plant and emission conditions were defined as 6 patterns from a combination of emission rates and the total number of particles of the $^{137}Cs$, using the WRF/HYSPLIT modeling system. Results and Discussion: The highest mean concentration of $^{137}Cs$ occurred at 0900 LST under the ME4_1 (main wind direction: SSW, daily average wind speed: $2.8ms^{-1}$), with a wide region of its high concentration due to the continuous wind changes between 0000 and 0900 LST; under the ME3 (NE, $4.1ms^{-1}$), the highest mean concentration of $^{137}Cs$ occurred at 1500 and 2100 LST with a narrow dispersion along a strong northeasterly wind. In the case of ME4_4 (S, $2.7ms^{-1}$), the highest mean concentration of $^{137}Cs$ occurred at 0300 LST because $^{137}Cs$ stayed around the KNPP under low wind speed and low boundary layer height. As for the emission conditions, EM1_3 and EM2_3 that had the maximum total number of particles showed the widest dispersion of $^{137}Cs$, while its highest mean concentration was estimated under the EM1_1 considering the relatively narrow dispersion and high emission rate. Conclusion: This study showed that even though an area may be located within the same radius around the Kori Nuclear Power Plant, the distribution and levels of $^{137}Cs$ concentration vary according to the change in time and space of weather conditions (the altitude of the atmospheric boundary layer, the horizontal and vertical distribution of the local winds, and the precipitation levels), the topography of the regions where $^{137}Cs$ is dispersed, the emission rate of $^{137}Cs$, and the number of emitted particles.

• 대기
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• 제18권3호
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• pp.171-182
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• 2008

In this study, we analyzed the spatial and temporal distribution of wind resources over Korea based on hourly observational data recorded over a period of 5 years from 457 stations belonging to Korea Meteorological Administration (KMA). The surface and 850 hPa wind data obtained from the Korea Local Analysis and Prediction System (KLAPS) and the Regional Data Assimilation and Prediction System (RDAPS) over a period of 1 year are used as supplementary data sources. Wind speed is generally high over seashores, mountains, and islands. In 62 (13.5%) stations, mean wind speeds for 5 years are greater than $3ms^{-1}$. The effects of seasonal wind, land-sea breeze, and mountain-valley winds on wind resources over Korea are evaluated as follows: First, wind is weak during summer, particularly over the Sobaek Mountains. However, over the coastal region of the Gyeongnam-province, strong southwesterly winds are observed during summer owing to monsoon currents. Second, the wind speed decreases during night-time, particularly over the west coast, where the direction of the land breeze is opposite to that of the large-scale westerlies. Third, winds are not always strong over seashores and highly elevated areas. The wind speed is weaker over the seashore of the Gyeonggi-province than over the other seashores. High wind speed has been observed only at 5 stations out of the 22 high-altitude stations. Detailed information on the wind resources conditions at the 21 stations (15 inland stations and 6 island stations) with high wind speed in Korea, such as the mean wind speed, frequency of wind speed available (WSA) for electricity generation, shape and scale parameters of Weibull distribution, constancy of wind direction, and wind power density (WPD), have also been provided. Among total stations in Korea, the best possible wind resources for electricity generation are available at Gosan in Jeju Island (mean wind speed: $7.77ms^{-1}$, WSA: 92.6%, WPD: $683.9Wm^{-2}$) and at Mt. Gudeok in Busan (mean wind speed: $5.66ms^{-1}$, WSA: 91.0%, WPD: $215.7Wm^{-2}$).

• 수산해양기술연구
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• 제28권4호
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• pp.385-397
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• 1992

Current measurements at 3 sections and numerical experiments were carried out in Masan Bay to understand the effect of the wind on the residual currents and pollutant transport. The vertical distribution of horizontal velocities were directly affected by the wind at the depths of 1m and 2m beneath the sea surface. Analysis of the velocity data suggested that changes in the vertical gravitational circulation contributed to the net circulation. The net transport of water through the northern part of the bay was observed to be landward, with wind-induced transport of about 100m super(3)/s. Hence, wind is concluded to be the dominant mechanism driving the net circulation in the northern area of Masan Bay. Numerical experiments are shown that when S wind with 5m/s blew, northern area of the bay was generated the horizontal circulation of clockwise and local gyre. On the contrary of those, N wind made her to the anti-clockwise. In the case of no wind, the tidal residual current(constant flow) is very small or neglected except the bay-mouth. The inflow or outflow pattern of the mouth is considered as the flows generated by tidal residual current only. The distance of wind-induced transport of pollutant was as long as 2 times of no wind during the one tidal period.