• 한국환경과학회지
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• 제25권7호
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• pp.1017-1028
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• 2016

Wind information is one of the major inputs for the prediction of urban air flow using computational fluid dynamic (CFD) models. Therefore, the numerical characteristics of the wind data formed at their mother domains should be clarified to predict the urban air flow more precisely. In this study, the formation characteristics of the wind data in the Seoul region were used as the inlet wind information for a CFD based simulation and were analyzed using numerical weather prediction models for weather research and forecasting (WRF). Because air flow over the central part of the Korean peninsula is often controlled not only by synoptic scale westerly winds but also by the westerly sea breeze induced from the Yellow Sea, the westerly wind often dominates the entire Seoul region. Although simulations of wind speed and air temperature gave results that were slightly high and low, respectively, their temporal variation patterns agreed well with the observations. In the analysis of the vertical cross section, the variation of wind speed along the western boundary of Seoul is simpler in a large domain with the highest horizontal resolution as compared to a small domain with the same resolution. A strong convergence of the sea breeze due to precise topography leads to the simplification of the wind pattern. The same tendency was shown in the average vertical profiles of the wind speed. The difference in the simulated wind pattern of two different domains is greater during the night than in the daytime because of atmospheric stability and topographically induced mesoscale forcing.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.226-231
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• 2011

This study set out to review the air current fluidity in exhaust common ducts by installing an inlet pipe at a leisure space in the PS(Pipe Shaft)room for the sake of wind power generation with kitchen and bathroom exhaust common ducts of all the equipment and air conditioning shafts in high-rise apartment. The air current functionality of kitchen and bathroom exhaust common ducts was reviewed by analyzing wind velocity changes according to changes to the area of exhaust common ducts through a simulation, changes to the wind velocity of the kitchen hood by applying an external inlet pipe, changes to the usage factor of exhaust common ducts, and changes to wind velocity by altering the form of the ventilator at the bottom of the old exhaust common duct. It was a basic study on the utilization of exhaust wind velocity in exhaust common ducts.

• 융합보안논문지
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• 제11권5호
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• pp.109-120
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• 2011

기상상황은 고금을 통해 인간의 생활이나 병법의 중요한 요소로 생존전략의 핵심적 역할을 해왔다. 현대 도시의 과밀집중현상은 여러 가지 문제를 야기하고 있으며, 고층화와 토지피복의 변화는 기상의 이상 현상을 일으키는 작용을 하고, 특히 도심지역의 바람길은 주변의 지배적인 기상여건과 다른 흐름이 나타나고 있다. 따라서 바람길은 도심지역에 위치한 국가 중요시설 등에 대한 위기관리를 위한 방어계획에 중요한 고려 요인이 될 수 있다. 특히 대기 중에 유출된 유독물질의 유해성은 비람길이 핵심적인 변인이 된다. 본 논문은 도심지역의 바람길의 산출과 이를 통한 국가 중요시설 및 지역에 대한 위기관리에 유용성을 논의하고, 방어계획의 수립에 활용하기 위한 방안을 도출하고자 하였다. 이는 화생방테러리즘이나 폭력적 집회 시위에 대한 방어계획의 수립, 대형 사고나 자연재난 시 주민대피계획의 수립에 유용할 것으로 사료된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.324-327
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• 2008

We simulated the performance improvement of a wind turbine installed on the pitched roof-building(apartment in urban area, 50m height). A nozzle shape wind guide is added on the roof of a model apartment. The nozzle-diifuser structure effects for the free stream wind (average 4m/s, 50m height in Incheon) is studied by a basic CFD analysis. This paper examines the effects of roof structure on the wind velocity and the wind distortion effects by a front building. The possible wind power generation capacity on building roof in urban is calculated.

• Wind and Structures
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• 제24권1호
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• pp.1-24
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• 2017

Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

• 한국태양에너지학회 논문집
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• 제23권2호
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• pp.21-34
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• 2003

This study aims to present the applicability of wind turbine generator system to urban buildings for the utilization of clean renewable energy. The results are as follows; According to the wind resource analysis, it has been found that small sized wind power system can be viable for buildings application due to the amplification of wind velocity around buildings or building clusters, in spite of low mean velocity of 2-3m/s in Seoul and Kyunggi urban areas. But planners must perform micrositing analysis around building so that wind turbine can be located at high velocity zones. The system must be designed to avoid obstacles preventing prevailing wind in buildings. It should be recognized that wind speeds are changing depending on the height and length from buildings. The wind power system can be used as a symbol of landmark which shows a sustainable architecture from the scenary Itself A case study for apartment building in urban showed that wind power systems can be applicable in two kinds of place, rooftops and ground levels. Especially, the wind power systems must be carefully positioned so that wind resources do not decrease when it is installed at ground levels. and according to life cycle cost analysis, adaption of new small win4 power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building height. This research will ultimately achieve green architecture that preserves nature and at the same time provides pleasant environment to humans, and will play a great role in establishing the environment-preserving sustainable architecture of the 21th century.

• Wind and Structures
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• 제26권1호
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• pp.45-56
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• 2018

Wind damage of urban trees arises to be a serious issue especially in the typhoon-prone areas. As a family of tree species widely-planted in Southeast China, the structural behaviors of Plane tree is investigated. In order to accommodate the complexities of tree morphology, a fractal theory based finite element modeling method is proposed. On-site measurement of Plane trees is performed for physical definition of structural parameters. It is revealed that modal frequencies of Plane trees distribute in a manner of grouped dense-frequencies; bending is the main mode of structural failure. In conjunction with the probability density evolution method, the fragility assessment of urban trees subjected to wind excitations is then proceeded. Numerical results indicate that small-size segments such as secondary branches feature a relatively higher failure risk in a low wind level, and a relatively lower failure risk in a high wind level owing to windward shrinks. Besides, the trunk of Plane tree is the segment most likely to be damaged than other segments in case of high winds. The failure position tends to occur at the connection between trunk and primary branches, where the logical protections and reinforcement measures can be implemented for mitigating the wind damage.

• Wind and Structures
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• 제24권1호
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• pp.59-78
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• 2017

Non-stationarity and non-Gaussian property are two of the most important characteristics of wind. These two features are studied in this study based on wind speed records measured at different heights from a 325 m high meteorological tower during the synoptic wind storms. By using the time-frequency analysis tools, it is found that after removing the low frequency trend of the longitudinal wind, the retained fluctuating wind speeds remain to be asymmetrically non-Gaussian distributed. Results show that such non-Gaussianity is due to the weak-stationarity of the detrended fluctuating wind speed. The low frequency components of the fluctuating wind speeds mainly contribute to the non-zero skewness, while distribution of the high frequency component is found to have high kurtosis values. By further studying the decomposed wind speed, the mechanisms of the non-Gaussian distribution are examined from the phase, turbulence energy point of view.

• 한국태양에너지학회 논문집
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• 제27권2호
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• pp.95-101
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• 2007

The surface changes due to urban expansion and the increase of artificial heat releases have brought significant climate changes such as heat island phenomenon in urban area. Furthermore, these changes also have brought serious problems such as air temperature increase, wind changes, and air pollution in urban area. Comprehensive analytical technologies considering various effects are required to analyse complicated mechanism of climate changes, and review the efficient measures. In this research, the effect of the urban expansion in Tokyo and Bangkok area on urban environment will be discussed. By using CFD, urban development and the mechanism of global warming and wind change are studied in those two cities. As a result of numerical research, the surface changes of city could bring the environmental changes in urban area.

• 대기
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• 제29권5호
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• pp.689-698
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• 2019

Air pollution in urban areas has become a serious problem in the recent years. Especially, high concentrations of particulate matter (PM) cause negative effects on human health. Several studies suggest urban forest as a tool for improving air quality because of the capability of forests in reducing PM concentrations through deposition and adsorption using leaf area. For this reason, the National Institute of Forest Science plans to install in-situ observation stations for PM and biogenic volatile organic compounds (BVOCs) on a national scale to verify the net effect of forests on urban air pollution. To measure the quantitative change of PM concentrations due to the urban forest, stations should be located within and outside the forest area with respect to atmospheric circulation. In this study, we analyze the wind direction at the potential measurement sites to assess suitable locations for detecting the effect of urban forests on air quality in five cities (i.e. Gwangju, Daegu, Busan, Incheon, and Ilsan). This technical note suggests effective locations of in-situ measurements by considering main wind direction in the five cities of this study. A measurement station network created in the future based on the selected locations will allow quantitative measurements of PM concentration and BVOCs emitted from the urban forest and help provide a comprehensive understanding of the forest capabilities of reducing air pollution.