CFD를 이용한 보행자 풍환경 평가 기법의 적합성 분석

엄정아,이승수,함희정 한국풍공학회 2022 한국풍공학회지 Vol.26 No.2

Recently, due to increased urbanization with high-rise buildings, there are growing concerns about the wind environment that threatens the safety of pedestrians as well as facility damage caused by the building wind. In order to reduce building wind damage, it is important to improve the wind environment of the urban environment by applying preemptive measures through the evaluation of the wind environment around buildings. Besides conventional wind tunnel tests, CFD has recently been accepted an alternative or a supplementary tool for the assessment of wind environment on the pedestrian level. As one of the practice in the field, MOLIT recently proposed Wind Environment Evaluation Guidelines Using CFD Analysis Techniques. This paper presents a computational study to confirm the feasibility of the pedestrian wind environment evaluation method using CFD based on the guideline. To verify the results of CFD, models and wind tunnel experiment data by provided by Architectual Institute of Japan were employed. Various grid configurations and numerical methods as well as varied wind directions were applied. The comparison between experimental data and the present results show that the grid refinement improves the accuracy and the pedestrian wind can be assessed by using CFD in spite of some deficit and room for improvements. More importantly, the gusts caused by the upwind and downwind in upwind region of the building, and vortex around the building were well simulated. 최근 도시 과밀화와 건축물 고층화로 인해 빌딩풍에 의한 시설 피해는 물론 보행자의 안전을 위협하는 풍환경에 대한 우려 가 커지고 있다 . 빌딩풍 피해 저감을 위한 방안으로 건축물 주변 풍환경 평가를 통해 도시의 풍환경을 개선하는 것이 중요하다 . 이를 위해 풍동실험을 대체하거나 보완하는 수단으로 최근 전산 유체역학 기법 (CFD)의 적용이 받아들여지고 있으며 , 국토교통부가 보행 자 풍환경 평가를 위한 CFD 활용 가이드라인을 제시한 바 있다 . 본 논문에서는 이 가이드라인의 적정성을 평가하기 위한 전산해석을 수행하였다 . CFD 결과의 검증을 위해 일본 건축학회가 제시한 모형과 풍동실험 결과를 사용하였다 . 평가결과 일부 위치에서 풍동 실 험값과 CFD 결과의 풍속 차이는 있으나 격자의 상세도가 정확도에 미치는 영향과 CFD를 이용한 보행자 풍환경 평가 가능성을 확인 하였다 . 또한 , 건물 주위의 상승풍 , 하강풍 및 와류 등으로 인한 돌풍이 잘 모사되고 있음을 확인하였다 .

도시 생태공원의 풍환경 평가 적용에 관한 고찰

김원술,정일원,권지혜 한국습지학회 2019 한국습지학회지 Vol.21 No.5

City parks play an important role in reducing the air pollution and mitigating the city heat island effect caused by global warming. However, from July 2020, restricted parks over 20-year will be partially lifted due to sunset regulation on parks. As a result, the government and local governments have been making efforts to revitalize parks, such as creating ecological parks and securing park sites. However, building winds generated by high-rise buildings constructed around ecological parks in the city may cause discomfort to pedestrians and threaten the ecosystems of plants and animal that live in ecological parks. There are no clearly proposed as standards for wind environment assessment in Korea, but also it has been rarely studied on pedestrian wind environment. In this study, wind environment studies have been reviewed to find the important parameters related to wind environment assessment. Further, wind climate analysis using wind data obtained by Seoul meterological station was performed to examine the possibility of applicability of the wind environment assessment on the city ecological parks. 도시공원은 지구온난화와 대기오염을 줄여주고 열섬현상을 완화시켜주는 중추적인 역학을 하고 있다. 그러나 도시공원 일몰제에 따른 2020년 7월 이후 도시공원 제한이 일부 해제될 예정이다. 이에 따라 정부와 지자체는 공원부지 확보와 더불어 생태공원 조성 등 공원 활성화를 위한 노력을 기울이고 있다. 그러나 도시공원 주변에 건설되고 있는 고층건축물에 의해 발생하는 빌딩풍은 보행자에게 불쾌감을 유발할 수 있고, 생태공원에 서식하고 있는 동·식물의 생태계를 위협할 수 있다. 우리나라의 풍환경 평가에 대한 기준은 명확하게 제안된 바가 없으며, 관련 연구 또한 찾아보기 힘들다. 따라서 본 논문에서는 국외풍환경 평가기준 및 관련 연구를 검토하여, 풍환경 평가 기준의 중요 인자를 도출하고, 국내 기상관측자료를 이용한 풍환경평가에 적용 가능성을 검토하였다.

신재생에너지 확대와 미래 환경변화 대응을 위한 중장기 발전방향 : 육상풍력 발전사업의 현황과 추진방향

이영준,김현구,박원서,박성우,박종윤,강유진 한국환경정책평가연구원 2020 기본연구보고서 Vol.2020 No.-

Ⅰ. 서론 1. 연구 배경 및 목적 □ 한국환경정책·평가연구원(KEI)이 2019년 9월 26~27일에 개최한 “신재생 에너지 확대와 미래 환경변화 대응을 위한 대토론회”에서 분야별 전문가들이 발표한 내용을 정리함 ㅇ 육상풍력 발전사업과 관련하여 우리나라 재생에너지 보급 정책의 성공적 추진에 필요한 관련 연구 현황 및 산업계의 입장에 대한 내용을 포함하여 정리함 - 제1장: 육상풍력발전의 기본적인 현황 및 환경적 쟁점 사항 - 제2장: 육상풍력 발전사업의 기술적 입지조건 분석을 통한 잠재량 산정 - 제3장: 육상풍력발전의 국내외 시장 및 기술동향 - 제4장: 지자체 주도형 계획입지의 필요성 및 도입방안 ㅇ 자연 보존과 청정에너지의 확대와 관련하여, 다각적 측면에서의 논의와 객관적 사실에 근거한 올바른 인식개선을 통해 이 두 가지가 상호 공존할 수 있는 방안을 살펴보고자 함 2. 육상풍력 발전사업의 환경적 쟁점 사항 □ 육상풍력 발전시설이 주로 입지하는 고지대 능선부는 식생이 우수하고 산림생태계가 잘 보전되고 있는 지역이 대부분임 ㅇ 주요 능선축에 인접한 육상풍력사업의 입지와 관련하여 지역 및 광역생태축과 이를 이루고 있는 우수한 자연생태환경의 보존이 환경적 관점에서 핵심 검토사항임 ㅇ 산줄기를 따라 설치되는 풍력기와 관리도로에 의해 생태계 단절 및 교란, 지형 훼손, 토사 유출, 생태계 생물종 변화 등 우려됨 ㅇ 풍력터빈이나 송전선로보다 풍력기 관리를 위해 설치되는 관리도로에서 가장 심각한 환경적 영향이 발생하며, 자연 서식지 상실, 숲 또는 기타 자연 서식지의 파괴, 토양 침식 및 산사태와 같은 영향이 큰 것으로 나타남 Ⅱ. 육상풍력 발전사업의 기술적 입지조건 및 시장 잠재량 1. 국내 풍력발전 현황 □ 우리나라 신재생에너지 보급은 1997년 12월에 「대체에너지개발 및 이용·보급촉진법」이 제정되면서 본격적으로 시작됨 ㅇ 2002년 5월부터 발전차액지원제도(FIT: Feed-In-Tariff)가 시행되었고, 2004년 12월 개정된 「신에너지 및 재생에너지 개발·이용·보급 촉진법」(약칭 「신재생에너지법」)으로 제도적 뒷받침이 강화됨에 따라 풍력단지(wind farm)가 본격적으로 개발되기 시작함 ㅇ 우리나라의 최근 10년간(2009∼2018년)의 풍력발전 연간 이용률은 22.6±2.0%로, 일본 19.5%, 중국 22.6%, 독일 18.7%에 비해 높은 수준이나 덴마크 27.2%, 스페인 25.2%, 영국 27.1%에 비해서는 낮은 수준임 2. 국내 풍력발전 잠재량 □ 우리나라 재생에너지 자원 잠재량은 산업통상자원부 산하 한국에너지공단이 신재생에너지 백서를 통하여 격년으로 발표하고 있음 ㅇ 시장 잠재량은 기술적 잠재량에 경제적 요인과 지원정책 및 규제정책 영향요인을 추가로 부과하여 산정함 ㅇ 우리나라 풍력발전의 평균 이용률은 IEA Wind 회원국 중 중위권인 22% 수준으로, 이는 우리나라의 풍력자원이 풍력발전에 부적합할 정도로 빈약하지 않다는 것을 반증함 ㅇ 하지만 풍력발전사업 인허가 과정에서 환경영향평가 및 주민동의 절차 등에 지나치게 많은 시간과 비용이 소모되어 경제성이 해외에 비해 상대적으로 떨어지고 있어 이를 개선할 수 있는 정책적인 수단이 필요함 Ⅲ. 육상풍력발전의 국내외 시장 및 기술동향 1. 해외 풍력발전 시장 동향 □ 2018년 현재, 세계 풍력시장의 누적 설치규모는 약 591GW에 달하며, 전 세계 총 전력공급의 약 5.6%를 담당하고 있음 ㅇ 풍력발전기 설치에 소요되는 건설공사 관련 투자비용을 합산하면 전체 풍력시장 규모는 약 1,000억 달러(한화 약 120조 원)에 달할 것으로 보임 2. 해외 풍력발전 기술 동향 □ 2000년대에 들어와서 1MW급의 풍력터빈이 개발되었고, 2010년 이후 2~3MW급으로 커졌으며, 2019년 현재 육상풍력 기준으로 4MW 및 5MW 발전용량의 신규 모델들이 출시됨 ㅇ 풍력발전의 발전단가는 지속적으로 하락하여, 2010년에 육상풍력의 발전단가는 MWh당 약 90달러이었으나, 2018년에는 약 50달러 밑으로 낮아지고 있음 ㅇ 유럽퓽력발전협회 자료에 따르면, 유럽지역에 설치된 풍력터빈은 평균 용량이 2014년에 약 2.8MW급이었으나, 2018년 현재 약 3.6MW급으로 대형화되고 있음 3. 국내 육상풍력 현황 및 과제 □ 2000년대 초부터 시작된 국내 풍력발전의 보급실적은 약 20년간 누적된 실적임에도 불구하고 총 1.3GW에 불과한 실정임 ㅇ 세계 시장에서의 점유율이 0.2%에 그쳐 하나의 산업으로 성장할 수 있는 기반이 매우 취약한 상태임 ㅇ 국내 설치된 풍력발전기 중 국산 터빈의 점유율은 2010년에 5.9%에 불과하였으며 나머지는 모두 외산 수입 터빈을 사용하였으나, 2018년 말에는 국산 비중이 52.3%까지 높아짐 ㅇ 풍력발전의 보급 확대를 위해서는 풍력발전을 둘러싼 환경적 가치에 대한 인식의 전환 등을 통하여 입지를 확보하는 것이 가장 중요함 Ⅳ. 지자체 주도형 계획입지의 필요성 및 도입방안 1. 재생에너지 보급 목표 및 현황 □ 우리나라의 재생에너지 보급을 촉진하기 위한 지자체 주도형 계획입지 도입방안을 제안함 ㅇ 국내 재생에너지의 보급 현황 및 장애요인을 파악하고, 국내외 유사 사례를 통해 시사점을 도출함 ㅇ 풍력발전은 입지규제 및 주민 수용성 문제 등으로 인해 2018년 보급 규모가 목표대비 84% 수준인 168MW, 2019년 상반기에도 목표대비 20.4%인 133MW에 그치는 등 원활한 보급·확산이 지체되고 있음 ㅇ 주요 육상풍력사업 80건의 장애요인을 분석한 결과, 입지 문제가 45%, 주민 수용성 확보의 어려움이 20%로 큰 비중을 차지하는 것으로 나타남 ㅇ 이와 관련하여 부지를 계획적으로 조성하여 수용성과 환경성을 사전에 확보하고자 「신재생에너지법」을 개정하여 지자체가 주도적으로 참여하는 계획입지제도 도입을 추진하고 있음 2. 국내외 사례 □ 외국의 사례를 살펴보면, 국가 또는 전담기관에서 발전개발예정지구를 지정하고, 공모를 통해 사업자를 선정하는 등 국가 주도의 계획입지제도를 도입하여 운영하고 있음 ㅇ 이들 국가는 계획입지제도를 통해 체계적인 신규 풍력발전사업을 발굴하여 난개발을 방지하고, 사업자가 안정적인 사업을 진행할 수 있게 함 ㅇ 인허가 절차 간소화 및 계통연계 지원 등을 통해 사업 추진을 촉진하고, 입찰을 통해 재정부담을 완화하며, 환경적 영향을 최소화하고, 주민들의 수용성이 높은 풍력발전 단지를 개발하여 운영하려는 노력을 하고 있음 ㅇ 국내에서는 제주특별자치도가 「제주특별자치도 설치 및 국제자유도시 조성을 위한 특별법」 제303조 및 제304조에 근거하여 계획입지제도와 유사한 풍력발전지구 지정제도를 운영하고 있음 3. 계획입지제도 도입방안 □ 계획입지제도는 풍력, 태양광 등 대규모 재생에너지 발전시설을 지자체 주도로 체계적으로 설치·운영할 수 있도록 지원하는 제도로서, 주민 수용성 및 환경성을 사전검토하며, 사업자의 개발이익이 지자체·지역주민과 공유되도록 설계하여야 함 ㅇ 지역주민 참여가 가능한 마을공모 방식을 병행하고, 지구개발 기본계획 심의 전에 전략환경영향평가를 실시하고, 지구개발 실시계획 승인 전에는 환경영향평가를 실시하여 사전에 환경성을 검토하여야 함 Ⅴ. 결론 및 제언 □ 향후 정부의 신재생에너지 확대 정책을 지속가능하게 추진하기 위해서는 산능선부를 따라 집중되는 육상풍력사업의 입지 타당성 검토 시 환경가치, 경제성, 사회적 수용성 등을 종합적으로 고려한 체계적인 검토가 이루어져야 함 ㅇ 정부의 재생에너지 정책의 성공적 이행을 위해서는 녹색가치 간의 충돌 문제를 해결할 수 있는 다양한 정책 및 해법이 필요함 ㅇ 산림 및 생태계를 훼손하는 재생에너지사업이 지속가능한 재생에너지 발전사업의 모델이 될 수 없다는 사회적 공감대도 확산되고 있음 ㅇ 국내 풍력 보급실적은 세계 시장 점유율 0.2%로 신규 설치 규모도 매년 약 100~200MW에 불과하여 사실상 하나의 산업으로 성장할 수 있는 기반이 매우 취약한 상태임 □ 정부는 산업통상자원부와 환경부를 중심으로 그동안 불거진 후유증과 문제점을 해결하기 위한 다양한 제도를 마련하고 있음 ㅇ 산업통상자원부, 환경부 등 관련 부처를 통하여 ‘육상풍력 입지지도’를 마련하고 발전사업 허가 이전에 입지컨설팅 실시를 의무화하도록 함 □ 환경 보존과 신재생에너지 확대가 상호 공존할 수 있는 다양한 정책 및 해법이 필요함 ㅇ 환경적 영향을 고려하여 가용한 입지와 규모를 파악하여 보급 목표를 설정한 후, 영향이 낮은 지역부터 우선적으로 사업을 추진하는 것이 필요함 ㅇ 계획입지제도 등을 도입하여 개발가능지역을 대상으로 자연보존 등급이 상대적으로 낮은 지역부터 입지의 우선순위를 정하여 사업을 확대 추진하는 전략이 필요함 Ⅰ. Introduction 1. Background and aims of research □ This report summarizes the presentations made by experts at the ‘Great Discussion on Future Changes Related to Expansion of Renewable Energy’ held on September 26, 2019 organized by the Korea Environment Institute (KEI). ㅇ to present the current status of related research and the industry’s position necessary to successfully implement the nation’s renewable energy supply policy in relation to onshore wind power ㅇ to discuss various aspects of nature conservation vs. expansion of clean energy and improve awareness based on objective facts. 2. Environmental issues in onshore wind power □ Most of the high-altitude mountain ridges where onshore wind power are located have excellent vegetation and well-preserved forest ecosystem. ㅇ Major mountain ridges correspond to the regional ecological axes related to the preservation of the excellent natural ecological environment. ㅇ Concerns about the disruption of ecosystems due to wind turbines and management roads installed along mountain ridges that would cause damage to the terrain, soil runoff, and changes in local species are the major issue. Ⅱ. Technical Requirement for Location and Market Potential of Onshore Wind Power 1. Status of domestic onshore wind power □ The supply of renewable energy in Korea began in earnest in December 1997 with the enactment of the Alternative Energy Development and Utilization and Dissemination Promotion Act. ㅇ The FIT (Feed-In-Tariff) has been in effect since May 2002. ㅇ The annual utilization rate of wind power generation in Korea for the last 10 years (2009-2018) is 22.6 ± 2.0%. 2. Potential of domestic onshore wind power □ New and Renewable Energy White Paper published every other year ㅇ Market potential is calculated by adding economic and support policy influences and regulatory policy impacts to the technical potential. ㅇ In the process of licensing the wind power project, the economic feasibility is relatively low due to excessive time and cost required by environmental impact assessment and procedures for residents' consent. Ⅲ. Trends in Domestic and Foreign Markets and Technology in Onshore Wind Power 1. Trend of foreign markets □ As of 2018, the cumulative installed capacity of wind power worldwide is about 591 GW, accounting for about 5.6% of the total global power supply. ㅇ The total wind power market will be approximately $100 billion (about 120 trillion won) if construction-related investment costs for installing wind turbines are added. 2. Trend of technology □ In the 2000s, 1 MW was first developed. Since 2010 and it has grown to 2 MW to 3 MW. As of 2019, new models with 4 MW and 5 MW power generation capacity had been released. ㅇ The unit price of wind power generation continues to decrease. In 2010 it was about $90 per MWh, but in 2018, it is fell below $50. 3. Status and issue of domestic onshore wind power □ The supply of domestic wind power, which began in the early 2000s, is only 1.3 GW in total. ㅇ Domestically produced turbines accounted for only 5.9% of the whole wind turbines were installed in Korea in 2010, but at the end of 2018 the proportion of domestic products increased to 52.3%. ㅇ It is important to secure sites for wind farms by changing the perception on environmental values of wind power. Ⅳ. Introduction of a Planned Location System Led by Local Governments 1. Goal and status of renewable energy supply □ The introduction of a planned location system led by local governments is proposed to promote the supply of renewable energy in Korea in order to secure residents’ acceptance and environmental feasibility in advance ㅇ The supply in 2018 was only 168 MW, 84% of the target. In the first half of 2019, it was only 133 MW(20.4% of the target). ㅇ According to the analysis of 80 major onshore wind power projects, 45% had location problems and 20% had difficulty in securing residents' acceptance. 2. Domestic and foreign examples □ In foreign cases, the government or state agencies designate a planned development zone and select a developer through a public offering. ㅇ They find new wind power projects systematically through the planned location system to prevent reckless development as well as enable developers to secure project stability. ㅇ Jeju Province operates a system for designating wind power zones similar to the planned location system. 3. Introduction of a planned location system □ It is designed to review the environmental feasibility and residents’ acceptability in advance and to share the benefits of development with local governments and local residents. Ⅴ. Conclusion and Suggestions □ In connection with the government's policy to expand renewable energy in the future, it is necessary to conduct a systematic review of the feasibility of the location of onshore wind power projects along the mountain area in consideration of environmental value, economic suitability, and social acceptability. □ The government is preparing various systems to solve the problems related to renewable energy mentioned above with the Ministry of Trade, Industry and Energy and the Ministry of Environment as the center. □ Various policies and solutions are needed to ensure that environmental conservation and renewable energy expansion coexist. □ An expansion strategy is needed to promote the wind power project by prioritizing regions which are classified as relatively lower grade zones by introducing a planned location system.

Statistical characteristics of sustained wind environment for a long-span bridge based on long-term field measurement data

Ding, Youliang,Zhou, Guangdong,Li, Aiqun,Deng, Yang Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.1

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Lian Shen,Yan Han,C.S. Cai,Guochao Dong,Jianren Zhang,Peng Hu 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

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.

Characteristics of Zonda wind in South American Andes

Acir M. Loredo-Souza,Adrian R. Wittwer,Hugo G. Castro,Matthew B.Vallis 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.6

This paper discusses some features and conditions that characterize the Zonda wind, focusing particularly on the implications for wind engineering applications. This kind of wind, typical of mountainous regions, is far from being adequately characterized for computational simulations and proper modeling in experimental facilities such as boundary layer wind tunnels. The objective of this article is to report the research works that are being developed on this kind of wind, describing the main obtained results, and also to establish some general guidelines for the proper analysis of the Zonda in the wind engineering context. A classification for the Zonda wind is indicated and different cases of structural and environmental effects are described. Available meteorological data is analyzed from the wind engineering point of view to obtain the Zonda wind gust factors, as well as basic wind speeds relevant for structural design. Some considerations and possible directions for the Zonda wind-tunnel and computational modeling are provided. Gust factor values larger than those used for open terrain were obtained, nevertheless, the basic wind speed values obtained are similar to values presented by the Argentinian Wind Code for three-second gust, principally at Mendoza airport.

Characteristics of Zonda wind in South American Andes

Loredo-Souza, Acir M.,Wittwer, Adrian R.,Castro, Hugo G.,Vallis, Matthew B. Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.6

This paper discusses some features and conditions that characterize the Zonda wind, focusing particularly on the implications for wind engineering applications. This kind of wind, typical of mountainous regions, is far from being adequately characterized for computational simulations and proper modeling in experimental facilities such as boundary layer wind tunnels. The objective of this article is to report the research works that are being developed on this kind of wind, describing the main obtained results, and also to establish some general guidelines for the proper analysis of the Zonda in the wind engineering context. A classification for the Zonda wind is indicated and different cases of structural and environmental effects are described. Available meteorological data is analyzed from the wind engineering point of view to obtain the Zonda wind gust factors, as well as basic wind speeds relevant for structural design. Some considerations and possible directions for the Zonda wind-tunnel and computational modeling are provided. Gust factor values larger than those used for open terrain were obtained, nevertheless, the basic wind speed values obtained are similar to values presented by the Argentinian Wind Code for three-second gust, principally at Mendoza airport.

종관 환경 변화에 따른 아격자 산악모수화와 고해상도 지면 자료가 WRF 모델의 바람장 모의에 미치는 영향

이현지,김기병,이준홍,신혜윰,장은철,임종명,임교선 한국기상학회 2022 대기 Vol.32 No.2

This study evaluates the simulated meteorological fields with a particular focus on the low-level wind, which plays an important role in air pollutants dispersion, under the varying synoptic environment. Additionally, the effects of subgrid-scale orography parameterization and improved topography/land-use data on the simulated low-level wind is investigated. The WRF model version 4.1.3 is utilized to simulate two cases that were affected by different synoptic environments. One case from 2 to 6 April 2012 presents the substantial low-level wind speed over the Korean peninsula where the synoptic environment is characterized by the baroclinic instability. The other case from 14 to 18 April 2012 presents the relatively weak low-level wind speed and distinct diurnal cycle of low-level meteorological fields. The control simulations of both cases represent the systematic overestimation of the low-level wind speed. The positive bias for the case under the baroclinic instability is considerably alleviated by applying the subgrid- scale orography parameterization. However, the improvement of wind speed for the other case showing relatively weak low-level wind speed is not significant. Applying the high-resolution topography and land-use data also improves the simulated wind speed by reducing the positive bias. Our analysis shows that the increased roughness length in the high-resolution topography and land-use data is the key contributor that reduces the simulated wind speed. The simulated wind direction is also improved with the high-resolution data for both cases. Overall, our study indicates that wind forecasts can be improved through the application of the subgridscale orography parameterization and high-resolution topography/land-use data.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Shen, Lian,Han, Yan,Cai, C.S.,Dong, Guochao,Zhang, Jianren,Hu, Peng Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

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.

Statistical characteristics of sustained wind environment for a long-span bridge based on long-term field measurement data

Youliang Ding,Guangdong Zhou,Yang Deng,Aiqun Li 한국풍공학회 2013 한국풍공학회지 Vol.17 No.1

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.