• Structural Engineering and Mechanics
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• 제66권2호
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• pp.273-283
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• 2018

Currently, the dynamic amplification effect of suction is described using the wind vibration coefficient (WVC) of external loads. In other words, it is proposed that the fluctuating characteristics of suction are equivalent to external loads. This is, however, not generally valid. Meanwhile, the effects of the ventilation rate of louver on suction and its WV are considered. To systematically analyze the effects of the ventilation rate of louver on the multi-dimensional WVC of ultra-large cooling towers under suctions, the 210 m ultra-large cooling tower under construction was studied. First, simultaneous rigid pressure measurement wind tunnel tests were executed to obtain the time history of fluctuating wind loads on the external surface and the internal surface of the cooling tower at different ventilation rates (0%, 15%, 30%, and 100%). Based on that, the average values and distributions of fluctuating wind pressures on external and internal surfaces were obtained and compared with each other; a tower/pillar/circular foundation integrated simulation model was developed using the finite element method and complete transient time domain dynamics of external loads and four different suctions of this cooling tower were calculated. Moreover, 1D, 2D, and 3D distributions of WVCs under external loads and suctions at different ventilation rates were obtained and compared with each other. The WVCs of the cooling tower corresponding to four typical response targets (i.e., radial displacement, meridional force, Von Mises stress, and circumferential bending moment) were discussed. Value determination and 2D evaluation of the WVCs of external loads and suctions of this large cooling tower at different ventilation rates were proposed. This study provides references to precise prediction and value determination of WVC of ultra-large cooling towers.

• KIEAE Journal
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• 제11권6호
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• pp.37-42
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• 2011

This Paper aims for analyzing the effect of opening types on wind-driven ventilation performance in basement parking lots of apartment. The scale model of basement parking lot was made, wind tunnel tests conducted. Wind pressure of three opening types was measured, wind pressure coefficient calculated. As the result, it showed that the air flow pattern of stack type opening was strongly changed by wind direction, but it was almost not at scuttle vent type. But, as for the difference of wind pressure coefficient, stack type opening was more than the other two types.

• 한국지리정보학회지
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• 제23권4호
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• pp.101-119
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• 2020

최근 도시의 미세먼지 및 열환경 개선을 위한 방안으로써 바람길을 고려한 도시숲인 바람길숲 조성사업이 전국적으로 추진되고 있다. 이에 본 연구에서는 바람길숲 조성사업 대상 도시 중 하나인 평택시를 사례로 바람길숲 조성 여건 분석(미세먼지 및 열환경 취약지역, 바람길숲 분포 현황, 바람길 특성)을 수행하고, 분석 결과를 바탕으로 평택시의 바람길숲 조성방향을 제안하였다. 미세먼지 및 열환경에 취약한 지역을 도출한 결과, 평택시의 동부생활권 내 시가지에서 미세먼지 및 열환경에 가장 취약한 것으로 나타났다. 특히, 미세먼지의 경우 평택화력발전소, 항만, 국도 1호선 등 산업단지 및 도로에서 배출량이 높았다. 바람길숲 현황을 파악한 결과, 평택시 내에는 소규모의 생성숲, 디딤·확산숲, 연결숲이 파편화되고 단절되어 분포하고 있었다. 평택시의 전반적인 바람길의 특징은 무봉산 등에서 생성된 찬공기가 평택시 내로 강하게 유입되고 북서방향으로 흘렀다. 따라서 평택시 내 존재하는 생성숲을 보전하고 장기적으로 확대해나가야 하며, 취약지역까지 찬공기가 유입될 수 있도록 디딤·확산숲 및 연결숲 조성이 중요하였다. 또한 미세먼지 발생이 심각한 산업단지 및 도로에는 미세먼지 차단을 고려한 연결숲을 조성하여 주변 지역으로 미세먼지가 확산되지 않도록 식재기법을 적용해야 한다. 본 연구는 평택시의 바람길숲 조성사업을 위한 근거자료로 활용될 수 있을 뿐만 아니라 기타 도시숲 조성 관리에 있어 기초자료로 활용될 수 있을 것이다.

• 설비공학논문집
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• 제15권6호
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• pp.543-550
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• 2003

In order to saving the energy for HVAC system of buildings, utilization of wind-induced cross ventilation is thought to be promising. However, utilization of natural ventilation alone is not sufficient for maintaining the human thermal-comfort such as in hot and humid regions. A hybrid air conditioning system with a controlled natural ventilation system, or combination of natural ventilation with mechanical air conditioning is thought to overcome the deficiency of wind-driven cross ventilation and to have significant effects on energy reduction. This paper describes a concept of hybrid system and propose a new type of hybrid system using radiational cooling with wind-induced cross ventilation. Moreover, a radiational cooling system is compared with an all-air cooling system. The characteristics of the indoor environment will be examined through CFD (Computational Fluid Dynamics) simulation, which is coupled with a radiation heat transfer simulation and with HVAC control in which the PMV value for the human model in the center of the room is controlled to attain the target value.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1427-1435
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• 2001

Air movement in wokplaces, whether resulting from a forced ventilation system or naturally occurring airflow, has a significant impact on occupational health. In a huge shipbuilding factory building, typical harmful factors such as fume or vaporized gas from welding and cutting of steel plates, and dusts from grinding give unpleasant feeling. From field data survey, the yearly dominant, wind directions for the shipbuilding factory building tested were northwest, northeast and southeast Among the three wind directions, the ventilation improvement was the worst for the northeastern wind. This study was focused on location of the opening vents in order to utilize the natural ventilation effectively. Instantaneous velocity fields inside the 1/1000 scale-down factory building model were measured using a 2-frame PIV system. The factory building model was embedded in an atmospheric boundary layer simulated in a wind tunnel. The modified vents improve the internal Ventilation flow with increasing the flow speed more than two times, compared with that of present vents.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.496-500
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• 2010

Understanding train-wind is the best method to know how to optimize subway ventilation system. The capacity and efficiency of the subway ventilation system are known by pressure and velocity while train runs. Analysis of the internal flow in subway tunnel and around subway station are studied using numerical methods. Characteristics of internal flow and influence of subway ventilation system for the subway station with platform screen door and tunnel are analyzed by unsteady state analysis. Velocity and pressure of train wind transformation are compared at around subway ventilation system and the internal flow is investigated at the subway tunnel.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.201-209
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• 2001

Some passenger cars with sunroofs open at tilted positions experience reverse flows into cabin rooms and wind noises much louder compared to other cars. In this study, flows around open sunroofs are numerically studied with the variations of body leakage. The effects of body leakage on ventilation and wind noise of a sun roof are examined, in particular. Furthermore, flow visualization, pressure, and noise measured from wind tunnel and road tests are presented. The results show that too small body leakage results in poor performance of ventilation and generates high wind noise around a sunroof. It is therefore very important to secure an adequate body leakage from the early design stage to achieve better performance of a sunroof as well as passengers' comfort related to HVAC(Heating, Ventilation, and Airconditioning).

• 한국농공학회논문집
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• 제57권6호
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• pp.21-33
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• 2015

Recently, the Korean government announced a new development plan for a large-scale greenhouse complex in reclaimed lands. Wind environments of reclaimed land are entirely different from those of inland. Many standard books for ventilation design didn't include qualitative standard for natural ventilation. In this study, natural ventilation rates were analyzed to suggest standard for ventilation design of venlo type greenhouse built on reclaimed land. CFD (Computational Fluid Dynamics) simulation models were designed according to the number of spans, wind conditions and vent openings. The wind profile at a reclaimed land was designed using ESDU (Engineering Sciences Data Unit) code. Using the designed CFD simulation model, ventilation rates were computed using mass flow rate and tracer gas decay method. Additionally computed natural ventilation rates were evaluated by comparing with ventilation requirements. As a result of this study, ventilation rates were decreased with increasing of the number of spans. Ventilation rates were linearly increased with increasing of wind speed. When the wind speed was $1.0\;m{\cdot}s^{-1}$, only side vent was open and wind direction was $45^{\circ}$, homogeneity of ventilation rate at 0~1 m height is the worst. Finally, chart for computing natural ventilation rate was suggested. The chart was expected to be used for establishing standard of ventilation design.

• 한국지리정보학회지
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• 제16권2호
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• pp.16-29
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• 2013

본 연구는 경상남도 창원시를 대상으로 MetPhoMod 모델링의 야간시간대 바람패턴결과를 이용하여 공기순환성 평가를 실시하였다. 공기순환성 평가는 바람의 지속성과 교란성의 평가지수를 이용하여 분석하였으며, 바람의 지속성은 바람패턴의 풍속, 바람의 교란성은 풍향의 다양성 결과를 활용하였다. 분석결과 도시지역 중 공기순환성이 취약한 지역은 봉림동, 용지동, 반송동 등으로 나타났으며, 특히 용지동과 상남동, 사파동의 고층아파트 및 상업지역, 단독주거지역에서 바람정체현상이 발생하는 것으로 확인되었다. 따라서 이러한 공기순환성이 취약하여 바람정체현상이 발생하는 지역에 대해 공간개선을 함으로써 바람의 유동이 원활할 수 있도록 조성되어야 할 것이며, 도시외곽에서 생성되는 바람이 지속적으로 유입될 수 있도록 개발계획차원에서 바람길 조성방안이 마련되어야 할 것으로 판단된다.

• 한국환경과학회지
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• 제13권4호
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• pp.367-376
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• 2004

In urban area, thermal pollution associated with heat island phenomena is generally regarded to make urban life uncomfortable. To overcome this urban thermal pollution problem, urban planning with consideration of urban climate, represented by the concept of urban ventilation lane, is widely practiced in many countries. In this study, the prevailing wind ventilation lane of a local winds in Daegu during the warm climate season was investigated by using surface wind data and RAMS(Reasonal Atmospheric Model System) simulation. The domain of interest is the vicinity of Daegu metropolitan city(about 900 $km^{2})$ and its horizontal scale is about 30km. The simulations were conducted under the synoptic condition of late spring with the weak gradient wind and mostly clear sky. From the numerical simulations, the following two major conclusions were obtained: (1)The major wind passages of the local circulation wind generated by radiative cooling over the mountains(Mt. Palgong and Mt. Ap) are found. The winds blow down along the valley axis over the eastern part of the Daegu area as a gravity flow during nighttime. (2)After that time, the winds blow toward the western part of Daegu through the city center. As the result, the higher temperature region appears over the western part of Daegu metropolitan area.