Pedestrian-level Comfort Research Articles

The role of building morphology on pedestrian level comfort in Northern climate

Due to the rapid densification of cities, improving outdoor comfort is becoming increasingly important. To address this need, the current study introduces a methodology to evaluate outdoor comfort in the proximity of typical buildings in Tallinn, Estonia. The microclimate simulation software ENVI-met was employed to investigate the outdoor comfort conditions. The research outcomes show that the building's form, height, density, and orientation change consistently the pedestrian comfort around the buildings. The findings suggest that the integrated analysis of different building morphologies, massing, orientation, and their influences on the surrounding microclimate, thermal, and wind comfort are important.

Predicting the influence of subtropical trees on urban wind through wind tunnel tests and numerical simulations

Better prediction of turbulent airflow around urban trees is necessary because it impacts urban pollutant dispersion, outdoor thermal comfort, energy efficiency, pedestrian-level comfort and urban heat island mitigation. A major challenge is how to obtain an accurate numerical model of the turbulent flow field around trees and an improved parameterization of the turbulent momentum deficit using the drag coefficient (Cd). To address this challenge, we use wind tunnel tests and real trees to measure Cd for four common subtropical tree species: Ficus microcarpa, Mangifera indica, Michelia alba and Bauhinia blakeana. The results show that the Cd of the four trees ranges from 0.523 to 0.932, and that the negative relationship between Cd and wind speed (U) can be expressed by the exponential formula Cd=a*U−b. A three-dimensional model of wind modification by trees is proposed, and its accuracy is verified with wind tunnel measurements. With precise Cd and model, the predictability of the influence of trees on urban wind in subtropical areas is enhanced (root mean square error RMSE ranging from 2.89 m/s to 0.45 m/s). Future development and applications of the numerical model will help provide useful guidelines for urban landscape management and sustainable urban planning in terms of urban ventilation.

Microclimatic comfort measurements evaluation of building physics: The effect of building form and building settled area, on pedestrian level comfort around buildings

Wind discomfort and the dangers that the wind may lead can be harmful in terms of comfort conditions of both indoor and outdoor environment of the building/buildings to be constructed or just completed. The extent of discomfort to pedestrian varies from inducing slightly unpleasant feeling to producing a falling down hazard. Typically, the cause of frequent occurrences of strong wind at pedestrian area is primary related to the configuration of building structures and/or topography in the vicinity of the pedestrian area. Depending on the characteristics of the wind including magnitude, uniformity, ambient temperature, and so on, the level of disturbance to users of pedestrian areas can be different. In this context, the regions where Necmettin Erbakan University temporary education buildings are located have a fairly intensive topography in terms of wind. Therefore, detailed analysis of the inside regions and the surrounding areas of education buildings in particular are performed in terms of microclimatic comfort and indoor energy recovery. Especially, the topography where university campus temporary educational buildings are located has very high wind climate conditions compared to the city of Konya climate conditions. In this study, pedestrian-level wind conditions around N.E.U. campus buildings and in urban areas and the topography of campus settlements were analyzed through on-site measurement with Delta OHM microclimatic instruments. The purpose of this study is to investigate the pedestrian-level comfort conditions around the project buildings suggested by concept architects together with microclimatic measurements of comfort conditions, in the light of current topographic and climatic conditions presented by the head architect. However, presentation of these topographic and microclimatic measurements around currently completed temporary classrooms of the university campus have not yet been completed. The topography of the university campus, which is at an altitude higher than that of Konya centrum, is exposed to an extremely high wind velocity. The pedestrian-level comfort conditions are measured using Delta OHM instrument. The study also aims to compare pedestrian-level comfort conditions at locations of various buildings. In addition, outdoor comfort survey was also conducted in the campus area. However, measurement results of the microclimatic measurement device, DeltaOHM, are evaluated in this study. It can be observed from the results that pedestrian-level comfort of current campus settlements around the buildings reach very discomforting levels. Since the university’s topography varies between very high and very low temperature levels and wind velocity values, climatic comfort problems are observed in the area. Some reasons for the discomfort problems observed in current settlement are; incorrect use of climatic parameters, incorrect directions of buildings, thermal effects due incorrect selection of materials used in constructions of buildings. In order to achieve thermal comfort, more studies are required on pedestrian-level comfort, use of passive design techniques such as correct direction of buildings and correct selection of materials utilized in the buildings based on their thermal effects. This would help university campus buildings consume less energy and maximize people’s satisfaction.

Computational evaluation of building physics—The effect of building form and settled area, microclimate on pedestrian level comfort around buildings

Wind discomfort and the dangers that the wind may lead can be harmful in terms of comfort conditions of both indoor and outdoor environment of the building/buildings to be constructed or just completed. The wind effects on a site can be divided in two as: mechanical wind effects and thermal wind effects. This study is specifically about mechanical wind stress and pedestrian wind comfort. Typically, the cause of frequent occurrences of strong wind at pedestrian area is primary related to the configuration of building structures and/or topography in the vicinity of the pedestrian area. Depending on the characteristics of the wind including magnitude, uniformity, ambient temperature, etc., the level of disturbance to users of pedestrian areas can be different. In this context, the regions where Necmettin Erbakan University (N.E.U.) temporary education buildings are located have a fairly intensive topography in terms of wind. Therefore, detailed analyses of the inside regions and the surrounding areas of education buildings in particular are performed in terms of microclimatic comfort and indoor energy recovery. Especially, the topography where the university campus temporary educational buildings are located has very high wind climate conditions comparing to the city of Konya, Turkey, climate conditions. In this study pedestrian level wind conditions around N.E.U. campus buildings and in urban areas and campus buildings settlements topography are analyzed by CFD FloEFD. The aim of the study is to analyze causes of wind nuisance in campus site area and around temporary education buildings, and compare and evaluate remedial measures. The results show that current campus settlement, around the buildings and amphi classes are seen to reach very discomforting levels in terms of in classroom comfort. Draft architectural campus temporary education buildings projects proposed by the author can improve on existing wind conditions where possible, and as a minimum, can not significantly degrade wind conditions especially when considering the safety criteria.

Prediction of building interference effects on pedestrian level comfort

This paper presents results concerning the interference effect created by two auxiliary buildings located upstream of a recreation area comprising seven pavilions. Both numerical and experimental simulations were used to conduct the analyses, and the experimental and numerical results are compared against each other for vertical velocity profiles at different locations. For the numerical simulation, the RANS equations were solved with the turbulence formulated by the k– ε RNG model. For the experimental work, a 1 175 scale model was tested in a low-speed wind tunnel.

A discussion of the components for a comprehensive pedestrian level comfort criterion

A discussion of the components for a comprehensive pedestrian level comfort criterion