• Wind and Structures
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• 제11권1호
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• pp.51-70
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• 2008

CFD is applied to evaluate pedestrian wind comfort at outdoor platforms in a high-rise apartment building. Model validation is focused on generic building sub-configurations that are obtained by decomposition of the actual complex building geometry. The comfort study is performed during the design stage, which allows structural design changes to be made for wind comfort improvement. Preliminary simulations are performed to determine the effect of different design modifications. A full wind comfort assessment study is conducted for the final design. Structural remedial measures for this building, aimed at reducing pressure short-circuiting, appear to be successful in bringing the discomfort probability estimates down to acceptable levels. Finally, the importance of one of the main sources of uncertainty in this type of wind comfort studies is illustrated. It is shown that the uncertainty about the terrain roughness classification can strongly influence the outcome of wind comfort studies and can lead to wrong decisions. This problem is present to the same extent in both wind tunnel and CFD wind comfort studies when applying the same particular procedure for terrain relation contributions as used in this paper.

• 국제초고층학회논문집
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• 제11권4호
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• pp.315-320
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• 2022

With the rapid development of urbanization the problems of pedestrian-level wind comfort and natural ventilation of tall buildings are becoming increasingly prominent. The velocity at the pedestrian level ($\overline{MVR}$) and variation of wind pressure coefficients $\overline{{\Delta}C_p}$ between windward and leeward surfaces of tall buildings were investigated systematically through numerical simulations. The examined parameters included building density ρ, height ratio of building α_H, width ratio of building α_B, and wind direction θ. The linear and quadratic regression analyses of $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were conducted. The quadratic regression had better performance in predicting $\overline{MVR}$ and $\overline{{\Delta}C_p}$ than the linear regression. $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were optimized by the NSGA-II algorithm. The LINMAP and TOPSIS decision-making methods demonstrated better capability than the Shannon's entropy approach. The final optimal design parameters of buildings were ρ = 20%, α_H = 4.5, and α_B = 1, and the wind direction was θ = 10°. The proposed method could be used for the optimization of pedestrian-level wind comfort and natural ventilation in a residential area.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.402-409
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• 2008

Wind loads and environments in realistic situations surrounded by neighboring buildings may be considerably different from those in idealized or simplified situations such as codes and standards. Interference effects of change in wind passage of a building group on wind loads and wind environments are reviewed. Wind-induced interference effects depend mainly on the building geometry and arrangement of these structures, their orientation and upstream terrain conditions. The most important factor among them may be the arrangement of building structures which can change the wind direction directly. Interference effects regarding wind loads are discussed with examples of window damages by typhoon and of pressure measurements in the boundary layer wind tunnel. Wind environment problems are also discussed, specially underlined on pedestrian comfort and safety. Various evaluation techniques or standards of wind environment are introduced. The change of wind velocity between the panel-type apartment buildings is examined, depending on the distance each other.

• Wind and Structures
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• 제1권4호
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• pp.337-349
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• 1998

A numerical and experimental study was performed for the wind flow field in one area, comprising a group of several pavilions separated by passageways, of the EXPO '98 - a World Exposition (Lisbon, Portugal). The focus of this study is the characterization of the flow field to assess pedestrian comfort. The predictions were obtained employing the Reynolds averaged Navier-Stokes equations with the turbulence effects dealt with the ${\kappa}-{\varepsilon}$ RNG model. The discretization of the differential equations was accomplished with the control volume formulation in a Cartesian coordinate system, and an advanced segregated procedure was used to achieve the link between continuity and momentum equations. The evaluation of the overall numerical model was performed by comparing its predictions against experimental data for a square cylinder placed in a channel. The predicted values, for the practical geometry studied, are in a good agreement with the experimental data, showing the performance and the reliability of the ${\kappa}-{\varepsilon}$ RNG model and suggesting that the numerical simulation is a reliable methodology to provide the required information.

• 대한건축학회논문집:구조계
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• 제35권8호
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• pp.169-176
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• 2019

The purpose of this study was to analyze outdoor thermal comfort of apartments planning characteristic of pedestrian height in Beijing, China. Selecting 322 apartment complexes with more than 1000 households and more than 10 buildings(including 10 buildings), mainly in Chaoyang District and Tongzhou District to select 32 basic layout types and then 12 typical layout types were select in 32 basic layout types. Finally, the simulation was conducted for the 12 typical layout types using the micro-climate model ENVI-met to evaluate the wind environment, the thermal environment and the comfort. The results of this study as follows: In the parallel arrangement, it has the best outdoor thermal comfort of Slab-East-Parallel(S/E/P). Next is Slab-South-Parallel(S/S/P), Tower-South-Parallel(T/S/P) in turn. In the stagger arrangement, Mixture-South-North and South Stagger-1(M/S/NSS-1) has the best outdoor thermal comfort and Slab-South-North and South Stagger(S/S/NSS), Tower-South-North and South Stagger(T/S/NSS), Mixture-South-North and South Stagger-3(M/S/NSS-3), Mixture-South-North and South Stagger-4(M/S/NSS-4), Mixture-South-North and South Stagger-2(M/S/NSS-2) in turn. In the cluster arrangement, Mixture-Mixture-Cluster-2(M/M/C-2) has the best outdoor thermal comfort and Mixture-Mixture-Cluster-3(M/M/C-3), Mixture-Mixture-Cluster-1(M/M/C-1) in turn. Due to the low wind speed and high air temperature, it is necessary to consider the layout types that can form the wind road at first, such as Mixture-South-North and South Stagger-1(M/S/NSS-1), Slab-South-North and South Stagger(S/S/NSS) and so on.

• Wind and Structures
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• 제34권6호
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• pp.483-497
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• 2022

Three-dimensional (3D) computational fluid dynamics (CFD) analysis of flow around a hipped-roof building representative of UK inland conditions are conducted. Unsteady simulations are performed using three variations of the k-ϵ RANS turbulence model namely, the Standard, Realizable, and RNG models, and their predictive capability is measured against current European building standards. External pressure coefficients and wind loading are found through the BS 6399-2:1997 standard (obsolete) and the current European standards (BS EN 1991-1-4:2005 and A1:20101). The current European standard provides a more conservative wind loading estimate compared to its predecessor and the k-ϵ RNG model falls within 15% of the value predicted by the current standard. Surface shear stream-traces and Q-criterion were used to analyze the flow physics for each model. The RNG model predicts immediate flow separation leading to the creation of vortical structures on the hipped-roof along with a larger separation region. It is observed that the Realizable model predicts the side vortex to be a result of both the horseshoe vortex and the flow deflected off it. These model-specific aerodynamic features present the most disparity between building standards at leeward roof locations. Finally, pedestrian comfort and safety criteria are studied where the k-ϵ Standard model predicts the most ideal pedestrian conditions and the Realizable model yields the most conservative levels.

• KIEAE Journal
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• 제12권3호
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• pp.27-32
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• 2012

In recent years, the quality of the outdoor thermal environment has come to be regarded as important as that of the indoor thermal environment. Since the outdoor thermal environment is composed of many elements and is affected by many factors, it is not easy to evaluate the impact of each factor separately. Hence, a comprehensive assessment method is required. In order to evaluate the pedestrian level comfort of an outdoor climate, it is necessary to investigate not only wind velocity but also various physical elements, such as temperature, moisture, radiation, etc. Prediction of wind and thermal environment for a large scale buildings is one of the most important targets for research. Wind and thermal change in a city area is a very complicated phenomenon affected by many physical processes. The purpose of this study is to develop a design plan for wind environment at a large Buildings. In this study, we analyze outdoor wind environment and thermal environment on buildings using the CFD (Computational Fluid Dynamics) method. The arrangement of building models is an apartment in Jeonju. These prediction of wind and thermal environment for a large scale buildings is necessary in a plan before a building is built.

• 예술인문사회 융합 멀티미디어 논문지
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• 제9권5호
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• pp.565-575
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• 2019

본 연구는 물리환경 및 미기후, 쾌적성이 외부활동 지속에 미치는 영향 도출을 목적으로 한다. 본 연구에서는 외부활동 지속에 영향을 미치는 요소로 도시 내 물리환경, 물리환경에 대해 외부공간 활동자가 느끼는 쾌적성, 미기후, 미기후에 대해 외부공간 활동자가 느끼는 쾌적성 등을 중심으로 접근했다. 이에 대한 분석을 위해서 2017년 중 봄, 여름, 겨울과 같이 세 계절에 대해서 외부공간 활동자가 느끼는 다양한 쾌적도에 대한 설문조사를 수행하였다. 설문조사 응답자가 설문조사에 응답하고 있는 동안에 주변 장소의 미기후에 대한 측정을 실시하였다. 이렇게 구축된 자료를 이용하여 효과적인 분석수행을 위해서 로짓회귀분석을 이용하였다. 분석결과, 물리환경 쾌적성의 용이성 및 안전성과 기후환경 쾌적성의 온도, 바람, 일사량 쾌적성 등은 외부공간의 활동 지속도와 유의미한 관계를 맺고 있었다. 머물기 및 대화 행위 보다는 걷기와 쇼핑 행위가 물리적 환경 및 기후환경에 보다 예민하게 영향을 받는 요소임을 도출했다.

• 한국방재안전학회논문집
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• 제6권1호
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• pp.79-86
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• 2013

본 논문은 안전한 보행환경 사업 대상지 선정지표 개선 방안을 위한 연구 과제로서, 그동안 차량 중심으로 도로 정책이 추진됨에 따라 최근 매년 2천명 이상의 보행자 사망사고가 발생하는 등 인간중심의 보행환경이 매우 열악한 실정으로 보행권이 심각하게 침해되어 왔다. 보행권은 공공의 안전보장, 질서 유지 및 복리 증진을 저해하지 않는 범위에서 국민이 쾌적한 보행환경에서 안전하고 편리하게 보행할 권리로서, 국가는 안전하고 편리하며, 쾌적한 환경을 마련해 주어야 할 의무가 있다. 최근 보행자 안전에 대한 관심이 증가되고 있으며, 안전하고 쾌적하며 건강한 보행환경 공간 조성을 위한 국가차원의 지원도 이루어지고 있다. 보행환경 불량 대상지에 대한 개선사업은 많은 비용이 수반됨에 따라 한정된 재원을 효율적으로 사용하여 최대한의 효과를 얻고 그 사업추진의 타당성에 대한 엄격한 사후평가가 이루어져야 한다. 그러나 현재 보행안전 및 편의증진에 관한 법률에 의거 보행환경 개선지구 지정의 법적근거는 마련되었으나, 안전한 보행환경 조성이라는 목적에 맞는 사업 대상지 선정지표는 마련되어 있지 못한 실정이다. 이에 본 연구에서는 그동안 연구되어온 안전한 보행환경 사업 대상지 선정 평가지표의 문제점을 검토하여 개선안을 제안하고자 하였다. 안전한 보행환경 조성이라는 사업목적에 맞게 사업대상지 선정 시에는 주민설문조사와 역사성을 평가지표에서 제외하고, 보행자 안전성과 보행환경 평가 이외에 보행공간 안전시설과 강풍 등 자연재난 및 잠재적 인적위험에 대한 재난 안전성 평가를 신설할 것을 제안하였다.