• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.879-891
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• 2018

In this study, the effects of urban redevelopment and building construction on the change of the detailed flows around the Pukyong National University (PKNU) campus located in the building-congested area was investigated using a CFD (computational fluid dynamics) model and GIS (geographic information system). For the analysis of the detailed flows before and after the constructions of the buildings around and within the campus, numerical simulations for the 16 inflow directions were performed before and after the construction. We used, as reference wind speeds at the inflow boundaries, the averaged wind speeds observed at the Gwangan light beacon (962) where there is no surrounding obstacle (i.e., building and terrain) acting as friction. We analyzed the area fractions in which wind speeds at z = 2.5 m changed after the construction for 16 inflow directions. The area fractions were relatively large in the east-south-easterly and southerly cases, because of the high-rise buildings constructed at the east and the apartment complex and the Engineering buildings constructed at the south of the PKNU campus. In the case of the easterly of which frequency is highest among the wind directions observed at the Daeyeon AWS (AWS 942) located inside the PKNU campus, the wind-speed change was not significant even after the constructions. It is shown that the building construction has affected the detailed flows around as well as even in the far downwind region of the constructed buildings. Also, it is shown that the GIS and CFD model are useful for analyzing the detailed flows in planning the urban redevelopment and/or building construction.

• Wind and Structures
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• v.29 no.4
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• pp.235-246
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• 2019

Wind loading is one of important loadings that should be considered in the design of large hyperbolic natural-draught cooling towers. Both external and internal surfaces of cooling tower are under the action of wind loading for cooling circulating water. In the previous studies, the wind loads on the external surface attracted concernedly attention, while the study on the internal surface was relatively ware. In the present study, the wind pressure on the internal surface of a 220 m high cooling tower is measured through wind tunnel testing, and the effect of ventilation rate of the packing layer on internal pressure is a major concern. The characteristics of internal wind pressure distribution and its effect on wind-induced responses calculated by finite element method are investigated. The results indicate that the wind loading on internal surface of the cooling tower behaves remarkable three-dimensional effect, and the pressure coefficient varies along both of height and circumferential directions. The non-uniformity is particularly strong during the construction stage. Analysis results of the effect of internal pressure on wind-induced responses show that the size and distribution characteristics of internal pressure will have some influence on wind-induced response, however, the outer pressure plays a dominant role in the wind-induced response of cooling tower, and the contribution of internal pressure to the response is small.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.143-153
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• 2011

Offshore wind power(OWP) is one of the most promising renewable energy and gives higher output than onland one due to stronger and consistent wind in offshore. it offsets shortcoming of noise, spatial limit and less affects scenery, and can be built in larger size. Korea has plenty of offshore wind resources as it is surrounded by the sea in three directions. This review describes recent progress in offshore wind turbine and substructure technology. Market trend in local and overseas, Number of papers published and patents registered are analysed.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.337-346
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• 2002

Wind tunnel pressure measurements and numerical simulations based on the Reynolds Stress Model (RSM) are compared with full and model scale data in the flow area of impingement, separation and wake for $60^{\circ}$ and $90^{\circ}$ wind azimuth angles. The phase averaged fluctuating pressures simulated by the RSM model are combined with modelling of the small scale, random pressure field to produce the total, instantaneous pressures. Time averaged, rsm and peak pressure coefficients are consequently calculated. This numerical approach predicts slightly better the pressure field on the roof of the TTU (Texas Tech University) building when compared to the wind tunnel experimental results. However, it shows a deviation from both experimental data sets in the impingement and wake regions. The limitations of the RSM model in resolving the intermittent flow field associated with the corner vortex formation are discussed. Also, correlations between the largest roof suctions and the corner vortex "switching phenomena" are observed. It is inferred that the intermittency and short duration of this vortex switching might be related to both the wind tunnel and numerical simulation under-prediction of the peak roof suctions for oblique wind directions.

• Atmosphere
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• v.25 no.3
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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.

• Journal of Environmental Science International
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• v.14 no.3
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• pp.311-325
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• 2005

Elements of atmospheric environment, temperature, humidity and wind, at the compus of KNU(Kyungpook National University) were investigated by the observations. The observed data were compared with those of DWS (Daegu Weather Station). The simulations of wind field and dispersions of polluted gases were conducted by MUKLIMO under the various conditions. The results show that the atmospheric environment of KNU are suitable but the campus does not play role as a heat sink in the city. The simulations of wind field show the air flows and wind channels in the campus clearly. The exhausted gases by motor vehicles on the northside street of campus affect very much to the campus with $NW(300^{\circ})$ wind. The running cars in the campus are also pollute much on the campus with the various wind directions. The characteristics of environmental conditions, various meteorological fields, wind channels, and dispersion of exhausted gases at the campus of KNU were understood quantitatively in the study.

• Atmosphere
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• v.25 no.4
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• pp.591-600
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• 2015

We have analyzed wind and eddy covariance data collected within roughness sublayer over sloping terrain. The study site is located on non-flat terrain with slopes in both south-north and east-west directions. The surface elevation change is smaller than the height of roughness element such as building and tree. This study examines the directional wind shear for data collected at three levels in the lowest 10 m in the roughness sublayer. The wind direction shear is caused by drag of roughness element and terrain-induced motions at this site. Small directional shear occurs when wind speed at 10 m is strong and wind direction at 10 m is southerly which is the same direction as upslope flow near surface at this site during daytime. Correlation between vertical shear of lateral momentum and lateral momentum flux is smaller over steeply sloped surface compared to mildly sloped surface and lateral momentum flux is not down-gradient over steeply sloped surface. Quadrant analysis shows that the relative contribution of four quadrants to momentum flux depends on both surface slope and wind direction shear.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.674-679
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• 1999

The effect of wind on the circulation in Kamak Bay in the southern sea of Korea was examined using a numerical shallow water model. The experiments were primarily focused on how the effect of wind influence the tidal residual current. According to wind directions, the residual currents were changed; the westerly wind created a strong anti-clockwise eddy in the northwestern area of the bay where the flow field is usually very weak; the easterly wind strengthened the flow field in the central area of the bay; the patterns of flow fields to the north and south winds were almost the same as one without the wind, although the flow field became slightly stronger, The model flirty reproduced features in the observed current field at Pyongsa.

• Journal of Environmental Science International
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• v.30 no.1
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• pp.19-28
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• 2021

To reduce pollution, decrease the production of carbon dioxide, and to maintain a secure supply of energy, interest continues to grow in the area of renewable energy especially since there is a finite supply of cheap oil. Wind energy is one of the most viable options to consider and supply part of the energy needed to reduce dependence on foreign oil. However, it is difficult to predict the wind speed in an environment with many obstacles such as buildings and trees and getting accurate dimensions of those obstacles is difficult particularly on sloped mountainous terrain. In this study a drone was used to create a 3-D map of the campus of the Catholic University of Pusan. The dimensions and elevations for the 3-D map were used to make a model of the school campus in the CFD program Envi-met. Simulations were run for five different wind directions and 4 different elevations to find the location that would give the highest electrical output for a wind turbine. When considering all of these variables it was found that the optimal location was above the Student Union which had a 40% higher wind speed and could produce 274% more electrical power than the original wind speed.

• Wind and Structures
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• v.38 no.3
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• pp.171-191
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• 2024

Wind Driven Rain (WDR) poses a significant threat to the building environment, especially in hurricane prone regions by causing interior and content damage during tropical storms and hurricanes. The damage due to rain intrusion depends on the total amount of water that enters the building; however, owing to the use of inadequate empirical methods, the amount of water intrusion is difficult to estimate accurately. Hence, the need to achieve full-scale testing capable of realistically simulating rain intrusion is widely recognized. This paper presents results of a full-scale experimental simulation at the NHERI Wall of Wind Experimental Facility (WOW EF) aimed at obtaining realistic rain characteristics as experienced by structures during tropical storms and hurricanes. A full-scale simulation of rain in strong winds would allow testing WDR intrusion through typical building components. A study of rain intrusion through a sliding glass door is presented, which accounted for the effects of multiple wind directions, test durations and wind speeds; configurations with and without shuttering systems were also considered. The study showed that significant levels of water intrusion can occur during conditions well below current design levels. The knowledge gained through this work may enhance risk modeling pertaining to loss estimates due to WDR intrusion in buildings, and it may help quantify the potential reduction of losses due to the additional protection from shuttering systems on sliding glass doors during winds.