Proximity effect on low-rise building surrounded by similar-sized buildings

Kim, Yong Chul; Tamura, Yukio; Yoon, Sung-Won

doi:10.1016/j.jweia.2015.08.011

Cited by 21 publications

(4 citation statements)

References 27 publications

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“…Additionally, the mean wind flow in the lee of the target cube, characterized by a reverse flow [18], may also affect the mean wind-speed distribution inside the leeward opening. A previous study by Kim et al [21] is in agreement with the lower mean wind speeds observed in the present study near the leeward opening. Moreover, the skimming-flow effect typically observed in the roughness arrays with coverage ratios of equal to or more than 25% [22,23] may also lead to this observation.…”

Section: Mean Flow Fieldsupporting

confidence: 94%

Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions

et al. 2021

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Understanding the characteristics of natural, wind-induced ventilation of buildings is essential for accurate predictions of ventilation flow rates; however, indoor ventilation is significantly influenced by surrounding buildings. Therefore, a series of wind-tunnel experiments were performed to clarify the relationship between outdoor and indoor air flows around and within a target cube model with several openings. Two surrounding building arrangements, namely square (SQ) and staggered (ST), were placed under the condition of a building coverage ratio of 25%. The results indicated that the wind speed near the windward openings on the streamwise faces showed 0.3 to the reference wind speed, whereas those on the lateral faces were less than 0.1; these numbers indicate that the opening positions significantly affect the mean indoor wind speed. Furthermore, the temporal fluctuations of velocities near the opening demonstrated that the introduction of the flow is significantly affected by turbulent flow due to the surrounding buildings. In addition, correlation between the outdoor and indoor air flows was observed. The highest correlations were obtained for both opening conditions with a certain temporal delay. This result indicates that indoor air flows become turbulent because of the turbulent flows generated by the surrounding outdoor buildings; however, slight temporal delays could occur between indoor and outdoor air flows. Although the present study focuses on the fundamental turbulent characteristics of indoor and outdoor air flows, such findings are essential for accurately predicting the ventilation flow rate due to turbulent air flows for sheltered buildings.

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Section: Mean Flow Fieldsupporting

confidence: 94%

Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions

et al. 2021

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“…Conversely, since the late 70's, the wind loads and flow fields have been investigated for low-rise buildings normally built in large groups. Recently, Kim et al (2015) found that the shielding effect of nearby buildings increase significantly with area density and recommended wind engineers to be cautious in their choices of aerodynamic coefficients. The study of the flow field and mutual interference of densely clustered high-rise buildings indicated that wind-induced aerodynamic interference can be negligible or not depending if the buildings are located downstream or upstream from the studied one (Dongmei et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Effects of surrounding objects on the thermal performance of passively ventilated greenhouses

Villagrán

Bojacá

2019

J Agricult Engineer

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The growing expansion of protected horticulture in many regions is occurring around densely populated areas where land for agriculture is scarce, expensive or is used for other purposes. Inexpensive plastic passively ventilated greenhouses are the common choice for protected cultivation in these developing regions. The objective of this work was to analyse the effect of surrounding constructions and natural obstacles on the thermal performance of two naturally ventilated greenhouses. A saw tooth type greenhouse (TCG), typical for Colombian production, and an optimised greenhouse (OG) alternative with greater ventilation areas were analysed using computational fluid dynamics (CFD) with and without the surrounding objects of a real environment. The results showed that air exchange rate of a greenhouse with restricted ventilation areas are greatly reduced when neighbouring objects are high enough. This ventilation restriction is intensified under low wind speed conditions. The temperature gradients of the OG greenhouse were lower than those of the TCG scenarios due to the increased ventilation rates. The rooftop ventilation index for the OG greenhouse was increased by 65% with respect to the TCG greenhouse index, resulting in a direct effect on the ventilation rates. An improved air exchange with the outside can be reached by increasing the greenhouse ventilation areas, especially the roof vents, to overcome the airflow restrictions imposed by the surrounding environment. This simulation exercise was validated with field temperature data collected for a real OG prototype built in the Bogota plateau, with results showing a similar pattern for the internal temperature gradient as exhibited by the CFD model.

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“…Wind-induced interference effects are strongly dependent on arrangement modes, building spacing, wind direction and the number of upstream buildings [78][79][80] . When the wind direction is perpendicular to the ridge and the greenhouses are arranged in parallel, they are mainly subject to the "shielding effect".…”

Section: Influences Of Group Greenhouses On Wind Pressurementioning

confidence: 99%

Wind pressure acting on greenhouses: A review

Nan¹,

Wang²,

Bai³

et al. 2021

International Journal of Agricultural and Biological Engineering

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Greenhouses are widely used in agricultural and horticultural production. With the characteristics of lightweight, small stiffness and high flexibility, greenhouses are sensitive to wind loads. In the calculation of wind loads, the wind pressure coefficient (Cp) is essential. The rationality of the value directly affects the safety and economy of greenhouses. Therefore, the Cp values estimation is one of the most important issues in the design of greenhouses. In order to make full use of the existing research results, in this study, three main methods for estimating Cp values were analyzed, namely, full-scale field experiment, wind tunnel experiment and numerical simulation. Five factors influencing the Cp values were then reviewed including greenhouse design parameters, greenhouse group, overhanging eaves, ventilation and wind direction. Based on the existing researches, suggestions for future development and research work were also put forward. Owing to the flexibility and deformability of greenhouses, the fluid-solid coupling method should be used to analyze the effects of vibrations on wind pressures. The interaction of building parameters (such as the number of spans, ridge height, roof shape and slope angle) and terrain around the greenhouse should be taken into consideration comprehensively. The destructive vortices occurred on the greenhouse should be further investigated.

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Proximity effect on low-rise building surrounded by similar-sized buildings

Cited by 21 publications

References 27 publications

Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions

Turbulence Effect of Urban-Canopy Flow on Indoor Velocity Fields under Sheltered and Cross-Ventilation Conditions

Effects of surrounding objects on the thermal performance of passively ventilated greenhouses

Wind pressure acting on greenhouses: A review

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