• 대기
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• 제25권3호
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• pp.449-459
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• 2015

Effects of buildings and topography on observation environment of surface wind in central regions of urban areas are investigated using a computational fluid dynamics (CFD) model. In order to reflect the characteristics of buildings and topography in urban areas, geographic information system (GIS) data are used to construct surface boundary input data. For each observation station, 16 cases with different inflow directions are considered to evaluate effects of buildings and topography on wind speed and direction around the observation station. The results show that flow patterns are very complicated due to the buildings and topography. The simulated wind speed and direction at the location of each observation station are compared with those of inflow. As a whole, wind speed at observation stations decreases due to the drag effect of buildings. The decrease rate of wind speed is strongly related with total volume of buildings which are located in the upwind direction. It is concluded that the CFD model is a very useful tool to evaluate location of observation station suitability. And it is expected to help produce wind observation data that represent local scale excluding the effects of buildings and topography in urban areas.

• 한국생산제조학회지
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• 제23권5호
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• pp.443-449
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• 2014

This study aims to develop a Flywheel Energy Storage System (FESS) that uses wind power produced when an urban train is in motion, by utilizing a mounted turbine. This system was designed to generate and store electric power from wind power of a travelling urban train. The flywheel was designed to continue rotation using a one-way clutch bearing installed in the turbine shaft pulley, even in cases where the urban train decelerates or stops. This FESS can generate an additional 44% of electric power in comparison to a system not equipped with a flywheel. The generated power and operational features of the FESS were evaluated and verified through a wind tunnel test. The results show that the electric power stored in the FESS could supply auxiliary power for urban train components or service equipment, such as charging mobiles, Wi-Fi modules, and electric lights.

• 한국대기환경학회지
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• 제16권5호
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• pp.511-520
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• 2000

The urban atmosphere is characterized by th difference in surface and atmospheric environment between urban and more natural area. To investigate th climatic effect of land use type and anthropogenic heat of urban on wind field, numerical simulations were carried out under typical summer synoptic condition. The wind model PNU_MCM(Pusan National University Mesoscale Circulation Model) is based on the three-dimensional Boussinesq equations, taking into account the hydrostatic assumption . Since lane-use differs over every subdivision on Pusan the surface energy budget model includes sub0grid parameterization scheme which can calculate the total heat flux over a grid surface composed of different surfaces. The simulated surface wind agrees well with the observed value, and average over 6 days which represent typical summer lan-sea breeze days, August 1998, i.e. negligible gradient winds and almost clear skies. Urbanization makes sea-breeze enhance at day and reduce land-breeze at night. The results show that contribution of land-use type is much larger than that of anthropogenic heat in Pusan.

• Wind and Structures
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• 제12권6호
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• pp.553-574
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• 2009

This paper presents statistical analysis results of wind speed and atmospheric turbulence data measured from more than 30 anemometers installed at 15 different height levels on 325 m high Beijing Meteorological Tower and is primarily intended to provide useful information on boundary layer wind characteristics for wind-resistant design of tall buildings and high-rise structures. Profiles of mean wind speed are presented based on the field measurements and are compared with empirical models' predictions. Relevant parameters of atmospheric boundary layer at urban terrain are determined from the measured wind speed profiles. Furthermore, wind velocity data in longitudinal, lateral and vertical directions, which were recorded from an ultrasonic anemometer during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of existing theoretical and empirical models. The objective of this study is to investigate the profiles of mean wind speed and atmospheric turbulence characteristics over a typical urban area.

• 한국방재학회지
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• 제2권4호
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• pp.40-47
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• 2002

Since it is important to understand the bio-climatic change in Seoul for ecological city planning in the future, this paper gives an overview on bio-climate analysis of urban environments at Seoul. We analyzed its characteristics in recent years using the observations of 24 of Automatic Weather Station (AWS) by Korea Meteorological Administration (KMA). In urbanization, Seoul metropolitan area is densely populated and is concentrated with high buildings. This urban activity changes land covering, which modifies the local circulation of radiation, heat and moisture, precipitation and creating a specific climate. Urban climate is evidently manifested in the phenomena of the increase of the air temperature, called urban heat Island and in addition urban sqall line of heavy rain. Since a city has its different land cover and street structure, these form their own climate character such as climate comfort zone. The thermal fold in urban area such as the heat island is produced by the change of land use and the air pollution that provide the bio-climate change of urban eco-system. The urban wind flow is the most important climate element on dispersion of air pollution, thermal effects and heavy shower. Numerical modeling indicates that the bio-climatic transition of wind wake in urban area and the dispersion of the air pollution by the simulations of the wind variation depend on the urban land cover change. The winds are separately simulated on small and micro-scale at Seoul with two kinds of kinetic model, Witrak and MUKLIMO.

• Wind and Structures
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• 제11권6호
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• pp.455-478
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• 2008

The present study aims to estimate the wind ventilation performance for pedestrian level domains from the air quality point of view. Three typical models of a dense urban area were considered and numerically simulated in order to examine the effects of the geometry of such models on wind flow characteristics, which in turn affect the air quality, within the pedestrian domain of a street canyon located within this area. The calculated flow fields were employed to estimate the exceedance probabilities within the study domain using a new approach: air exchange rate within the domain. The study has been applied to nine cities in Japan: Tokyo, Osaka, Sapporo, Niigata, Fukuoka, Nagoya, Sendai, Yokohama, and Kyoto, based on their mean wind velocity data. The results demonstrated that the exceedance probability analysis of the pedestrian wind environment could be a valuable tool during the design stage of inhabited areas for the evaluation of pollutant-removal efficiency by the applied wind. Also, the calculated probabilities demonstrated substantial dependence on both the geometry of building arrays and the wind conditions of the nine cities.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.571-574
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• 2010

Large-eddy simulation has been conducted to simulate turbulent boundary-layer flows over an array of regularly distributed obstacles considering various cases of a wind incident angle. The effect of wind direction was investigated in the square cube array that periodic boundary condition was imposed. Characteristics of the turbulent flow over the obstacle array have been found to be very sensitive to the direction of prevailing wind or of mean wind or of mean pressure gradient but varied with height, specially below the urban canopy. Turbulent statistics are changed sensitively with the direction of mean pressure gradient around 10 degree.

• 신재생에너지
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• 제18권4호
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• pp.22-37
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• 2022

Large-scale offshore wind power is emerging as a viable solution to achieve carbon neutrality and solve climate change. As power generation complexes require ample space for construction, they create conflicts with residents near the construction site. To resolve the issue with residents, Korea, along with other countries, has developed policies that focus on influencing public perception. However, as the contents of such policies changed several times in a short period in Korea, they were differently applied depending on the timing of the project. This study examines how Korean offshore wind power site development policies, particularly the ones focusing on swaying public perception, were applied differently by regions.

• 한국지능시스템학회논문지
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• 제19권6호
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• pp.766-772
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• 2009

일반적으로 풍력발전은 광범위한 영역에 지속적인 바람을 요구하는 대형 시스템 위주로 개발이 되어왔다. 그러나 소형 풍력발전 시스템은 사용자에게 보다 친숙하고, 대형에 비해 보다 광범위한 적용이 가능하다는 점 때문에 최근 이에 대한 관심이 증가되고 있는 실정이다. 이에 본 연구에서는 배터리 충전에 효과적으로 도입될 수 있는 도시형 풍력발전을 위한 프로토타입 시스템에 대해 기술하며, 프로토타입 시스템에 효과적으로 도입될 수 있는 인공신경망 기반의 최대 전력점 추종 알고리즘을 제안하고자 한다. 또한 Matlab기반의 다양한 시뮬레이션 및 실제 시스템 설계를 통해 제안된 기법의 유용성을 확인하고자 한다.

• 한국태양에너지학회 논문집
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• 제30권2호
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• pp.22-32
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• 2010

The world is facing environmental problem described as climate change and exhaustion of fossil fuel. In order to solve theses problems, importance of renewable energy is extremely growing. For stable energy supply, it is need to apply hybrid renewable energy systems in urban-scale, because some renewable energy system' outputs are greatly influenced by climatic condition. Especially, solar irradiation and wind velocity are influenced by urban geometric environment as well as climatic condition. Therefore it is necessary to evaluate the renewable energy potential according as urban form. This study aims to evaluate the potential of solar energy and wind energy in urban-scale and classify urban type according as characteristics of urban forms. The results of this study will be used to develop renewable energy system application guidelines for urban and energy planning.