• Title, Summary, Keyword: Local wind

Search Result 607, Processing Time 0.04 seconds

Analysis of Local Wind in Busan Metropolitan Area According to Wind Sector Division - Part III : Division of Local Wind Sector over Busan - (바람권역 구분을 통한 부산지역 국지바람 분석 - Part III : 부산지역 상세 바람권역 구분 -)

  • Jung, Woo-Sik;Lee, Hwa-Woon;Park, Jong-Kil
    • Journal of Environmental Science International
    • /
    • v.16 no.3
    • /
    • pp.311-321
    • /
    • 2007
  • We have investigated coarse wind sectors in Busan metropolitan area and simulated detailed wind field using local atmospheric circulation model, RAMS in preceding studies (Part I, Part II). In this study, we divided and analyzed local wind sector in Busan according to the preceding results. We found that Busan metropolitan area is divided into 2 or 3 local wind sector in each coarse wind sector. The 9 coarse wind sectors were classified into 20 local wind sectors in total. But three local wind sectors were finally excluded because of these sectors were located on the complex hill area and the sea. Local wind sectors, therefore, in Busan metropolitan area were defined as 17 regimes. We assessed the location of air qualify monitoring sites at Busan metropolitan area using the information of these wind sectors. Most of these were located at proper points, but 6 sites were placed at 3 local wind sectors as a couple and no site was set up at 3 other sectors. Hence the location of these sites was in need of rearrange.

Comparative Analysis of Wind Flows in Wind Corridor Based on Spatial and Geomorphological Characteristics to Improve Urban Thermal Environments (도시 열환경개선을 위한 공간지형적 특성에 따른 바람길 유동 비교 분석)

  • SEO, Bo-Yong;JUNG, Eung-Ho
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.20 no.2
    • /
    • pp.75-88
    • /
    • 2017
  • This study analyzed wind flows based on spatial and geomorphological characteristics of Daegu Metropolitan City. A three-stage analysis was performed, starting with a comparison of meteorological relationships between local wind direction (synoptic wind) and local wind flow. In the second stage the study area was subdivided into districts and suburban districts to analyze the relative change of local wind flow. In stage three, the formation of wind corridor for local wind flow, wind flow for the entire urban space, and spatial relationships between flows were verified comparatively using KLAM_21. Three results are notable, the first of which is a low correlation between synoptic wind of a region, and local wind, flow in terms of meteorology. Secondly, observations of local wind flow at five downtown districts and two suburban districts showed that there were diverse wind directions at each measurement point. This indicates that the spatial and geomorphological characteristics of areas neighboring the measurement points could affect the local wind flow. Thirdly, verifying the results analyzed using KLAM_21, compared to Atomatic Weather System(AWS) measurement data, confirmed the reliability of the numerical modelling analysis. It was determined that local wind flow in a city performs a spatial function and role in ameliorating the urban heat island phenomena. This indicates that, when an urban planning project is designed, the urban heat island phenomena could be ameliorated effectively and sustainably if local wind flow caused by immediate spatial and geomorphological characteristics is confirmed systematically and techniques are intentionally applied to connect the flows spatially within areas where urban heat islands occur.

Estimation of Wind Pressure Coefficients on Even-Span Greenhouse Built in Reclaimed Land according to Roof Slop using Wind Tunnel (풍동을 이용한 간척지 내 양지붕형 온실의 지붕 경사에 따른 풍압계수 평가)

  • Kim, Rack-Woo;Kim, Dong-Woo;Ryu, Ki-Cheol;Kwon, Kyeong-Seok;Lee, In-Bok
    • Protected Horticulture and Plant Factory
    • /
    • v.23 no.4
    • /
    • pp.269-280
    • /
    • 2014
  • To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

Analysis of Design Wind Load Level for System Supports Considering Local Basic Wind Velocity and Construction Period (지역별 기본풍속과 공사기간을 반영한 시스템 동바리 설계 풍하중 분석)

  • Lee, Sun-Woo;Won, Jeong-Hun;Mha, Ho-Seong
    • Journal of the Korean Society of Safety
    • /
    • v.29 no.2
    • /
    • pp.53-61
    • /
    • 2014
  • This study evaluated wind loads considering a local basic wind velocity and construction periods to define the level of applied wind loads for system supports. Structural responses of system supports were examined and compared to those of system supports with the level of wind loads following various standards and specifications for permanent and temporary structures. And, the maximum combined stress ratios were estimated to evaluate the structural safety of a considered system support. From results, it was found that the wind load level should be applied in accordance with construction periods when estimating the safety of system supports. Looking into the response by change of the basic wind velocity according to local regions, it is no need to consider wind loads in regions with the basic wind velocity of 30 m/s. However, it was analyzed that wind loads should be considered in the regions with the basic wind velocity of 40 m/s or above. In addition, wind loads should be considered in designing system supports located at the region with the basic wind velocity of 35 m/s starting from construction period of 1.5 years. The standard specification for temporary work was analyzed as an incorrect standard in evaluating wind loads, since it underestimated the response of system supports in accordance with the local basic wind velocity and construction periods.

Numerical Simulation of Ozone Concentration using the Local Wind Model in Pusan Coastal Area, Korea (부산연안역에서 국지풍모델을 이용한 오존농도의 수치모의)

  • Jeon, Byung-Il;kim, Yoo-Keun;Lee, Hwa-Woon
    • Journal of Environmental Science International
    • /
    • v.6 no.4
    • /
    • pp.335-350
    • /
    • 1997
  • Numerical simulations of photochemical air pollution (CBM: Carbon-Bond Mechanisms under a theoretical three-dimensional local wind system are carried to clarify the fundamental characteristics of the effects of local wind on photochemical air pollution. According to the AWS data of Pusan coastal area and KMA, the surface wind of Pusan during summertime showed a very remarkable land and sea breeze circulation. The ozone concentration distribution using local wind model showed that high ozone concentration zone near coastal area moved toward inland In the afternoon. This change implies a sea breeze Increases the ozone concentration, but a land breeze decreases it in Pusan coastal area.

  • PDF

Evaluation of Energy Production for a Small Wind Turbine by Considering the Geometric Shape of the Deokjeok-Do Island (덕적도 지형을 고려한 소형풍력발전기 발전량 평가)

  • Jang, Choon-Man;Lee, Sang-Moon;Jeon, Wan-Ho;Lim, Tae-Gyun
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.25 no.6
    • /
    • pp.629-635
    • /
    • 2014
  • This paper presents annual energy production (AEP) by a 1.5kW wind turbine due to be installed in Deokjeok-Do island. Local wind data is determined by geometric shape of Deokjeok-Do island and annual wind data from Korea Institute of Energy Research at three places considered to be installed the wind turbine. Numerical simulation using WindSim is performed to obtain flow pattern for the whole island. The length of each computation grid is 40 m, and k-e turbulence model is imposed. AEP is determined by the power curve of the wind turbine and the local wind data obtained from numerical simulation. To capture the more detailed flow pattern at the specific local region, Urumsil-maul inside the island, fine mesh having the grid length of 10m is evaluated. It is noted that the input data for numerical simulation to the local region is used the wind data obtained by the numerical results for the whole island. From the numerical analysis, it is found that a local AEP at the Urumsil-maul has almost same value of 1.72 MWh regardless the grid resolutions used in the present calculation. It is noted that relatively fine mesh used for local region is effective to understand the flow pattern clearly.

Atmospheric Dispersion of Radioactive Material according to the Local Wind Patterns around the Kori Nuclear Power Plant using WRF/HYSPLIT Model (WRF/HYSPLIT 모델을 이용한 고리원전 인근 국지바람 패턴에 따른 방사성물질 대기확산 특성)

  • An, Hye Yeon;Kang, Yoon-Hee;Song, Sang-Keun;Bang, Jin-Hee;Kim, Yoo-Keun
    • Journal of Environmental Science International
    • /
    • v.24 no.1
    • /
    • pp.81-96
    • /
    • 2015
  • The characteristics of atmospheric dispersion of radioactive material (i.e. $^{137}Cs$) related to local wind patterns around the Kori nuclear power plant (KNPP) were studied using WRF/HYSPLIT model. The cluster analysis using observed winds from 28 weather stations during a year (2012) was performed in order to obtain representative local wind patterns. The cluster analysis identified eight local wind patterns (P1, P2, P3, P4-1, P4-2, P4-3, P4-4, P4-5) over the KNPP region. P1, P2 and P3 accounted for 14.5%, 27.0% and 14.5%, respectively. Both P1 and P2 are related to westerly/northwesterly synoptic flows in winter and P3 includes the Changma or typhoons days. The simulations of P1, P2 and P3 with high wind velocities and constant wind directions show that $^{137}Cs$ emitted from the KNPP during 0900~1400 LST (Local Standard Time) are dispersed to the east sea, southeast sea and southwestern inland, respectively. On the other hands, 5 sub-category of P4 have various local wind distributions under weak synoptic forcing and accounted for less than 10% of all. While the simulated $^{137}Cs$ for P4-2 is dispersed to southwest inland due to northeasterly flows, $^{137}Cs$ dispersed northward for the other patterns. The simulated average 137Cs concentrations of each local wind pattern are $564.1{\sim}1076.3Bqm^{-3}$. The highest average concentration appeared P4-4 due to dispersion in a narrow zone and weak wind environment. On the other hands, the lowest average concentration appeared P1 and P2 due to rapid dispersion to the sea. The simulated $^{137}Cs$ concentrations and dispersion locations of each local wind pattern are different according to the local wind conditions.

Analysis of local vibrations in the stay cables of an existing cable-stayed bridge under wind gusts

  • Wu, Qingxiong;Takahashi, Kazuo;Chen, Baochun
    • Structural Engineering and Mechanics
    • /
    • v.30 no.5
    • /
    • pp.513-534
    • /
    • 2008
  • This paper examines local vibrations in the stay cables of a cable-stayed bridge subjected to wind gusts. The wind loads, including the self-excited load and the buffeting load, are converted into time-domain values using the rational function approximation and the multidimensional autoregressive process, respectively. The global motion of the girder, which is generated by the wind gusts, is analyzed using the modal analysis method. The local vibration of stay cables is calculated using a model in which an inclined cable is subjected to time-varying displacement at one support under global vibration. This model can consider both forced vibration and parametric vibration. The response characteristics of the local vibrations in the stay cables under wind gusts are described using an existing cable-stayed bridge. The results of the numerical analysis show a significant difference between the combined parametric and forced vibrations and the forced vibration.

Analysis of hurricane directionality effects using event-based simulation

  • Huang, Zhigang;Rosowsky, David V.
    • Wind and Structures
    • /
    • v.3 no.3
    • /
    • pp.177-191
    • /
    • 2000
  • This paper presents an approach for evaluating directionality effects for both wind speeds and wind loads in hurricane-prone regions. The focus of this study is on directional wind loads on low-rise structures. Using event-based simulation, hurricane directionality effects are determined for an open-terrain condition at various locations in the southeastern United States. The wind speed (or wind load) directionality factor, defined as the ratio of the N-year mean recurrence interval (MRI) wind speed (or wind load) in each direction to the non-directional N-year MRI wind speed (or wind load), is less than one but increases toward unity with increasing MRI. Thus, the degree of conservatism that results from neglecting directionality effects decreases with increasing MRI. It may be desirable to account for local exposure effects (siting effects such as shielding, orientation, etc.) in design. To account for these effects in a directionality adjustment, the factor described above for open terrain would need to be transformed to other terrains/exposures. A "local" directionality factor, therefore, must effectively combine these two adjustments (event directionality and siting or local exposure directionality). By also considering the direction-specific aerodynamic coefficient, a direction-dependent wind load can be evaluated. While the data necessary to make predictions of directional wind loads may not routinely be available in the case of low-rise structures, the concept is discussed and illustrated in this paper.

Wind-induced Spatial and Temporal Variations in the Thermohaline Front in the Jeju Strait, Korea

  • Han, In-Seong;Suh, Young-Sang;Seong, Ki-Tack
    • Fisheries and aquatic sciences
    • /
    • v.16 no.2
    • /
    • pp.117-124
    • /
    • 2013
  • We investigated the short-term and local changes in the thermohaline front in the Jeju Strait, Korea, which is usually formed during winter and spring. To do so, we compared Real-Time Observation System by Ferryboat (RTOSF) data with wind data and routinely collected oceanographic data. During February and April 2007, a thermohaline front formed in the Jeju Strait around the 13-$14^{\circ}C$ isotherms and 33.0-33.5 isohalines. The thermohaline was clearly weakened and began moving southward in mid-March. The variations in the surface temperature and salinity showed a continuous north-south oscillation of the thermohaline front with a period of 3-10 days. The speed of the short-term and local fluctuation of thermohaline front was about 5-30 cm/s. We confirmed these findings by examining the variation in the maximum temperature gradient and $14^{\circ}C$ isotherm during the study period. These short-term and local changes had not been previously detected using serial oceanographic and satellite data. Analysis of local wind data revealed a northerly wind fluctuation with a period of 3-10 days, which was clearly related to the short-term and local changes in the thermohaline front. The short-term and local changes of the thermohaline front in the Jeju Strait originated from local changes in the winter monsoon in this area.