Wind Comfort Research Articles

Evaluation of the wind comfort of a person in the Krasnodar territory

The purpose of the study is to analyze and identify the most unfavorable pedestrian comfort zones in the Krasnodar Territory. The article uses a methodology for assessing pedestrian comfort, which takes into account the distribution of wind speeds along the wind rose, the pulsation component and the average wind speed, the duration of the manifestation of wind speeds in a certain direction. The assessment of comfort occurs according to three levels of comfort, the excess of which indicates the negative impact of wind on a person. As a result of the work, calculations were carried out according to the methodology used. Cartographic materials have been created and the most unfavorable wind zones have been identified, where the critical value of pedestrian comfort is exceeded.

Architectural Knitted Windbreaks for Improved Wind Comfort in the City: A Wind Tunnel Study of Custom-Designed Porous Textile Screens

There is a need to shield from the wind to improve pedestrian comfort in urban environments. Perforated windbreaks, such as fences, vegetation or textile nets, have proven to be an efficient solution, whereas knitted textiles have not yet been explored. The purpose of this study was to evaluate the capacity of knitted textile windbreaks to reduce wind velocities, to inform further research and promote wider architectural applications. Five custom-knitted textile prototypes, representing fragments of textile windbreaks, were tested in a wind tunnel and compared against a perforated and a nonperforated solid board. Forces on the models, as well as upstream and downstream velocities, were measured. The results indicate that the optimal optical porosity of knitted windbreaks should be around 10%, which differs from the porosity for perforated windbreaks recommended by prior studies. Moreover, it was observed that a textile windbreak knitted using the drop-stitch technique efficiently reduces the wind, while not generating a large drag force. Furthermore, the drag coefficient for the knitted windbreak is reduced with increased windspeed. With this, the presented study demonstrates that knitted structures exposed to wind influence have the functional potential of becoming efficient windbreaks, thus improving wind comfort and aesthetic user experience in the urban space.

Improving the pedestrian-level wind comfort by lift-up factors of panel residence complex: Field-measurement and CFD simulation

High-rise buildings in modern cities can hinder airflow and cause a weak local wind condition that intensifies pedestrian-level thermal discomfort. The lift-up design has been recognized as an effective way to improve wind comfort at pedestrian height levels due to its wind amplification effect. However, previous research has focused mainly on isolated buildings, while the influences of lift-up factors and their interactions on the pedestrian-level wind comfort have not been studied comprehensively enough. Therefore, this study aims to investigate the effects of lift-up ratio and positions of lift-up design on the pedestrian-level wind environments around a residence complex by combining field measurement and Computational Fluid Dynamics (CFD) simulation. An array of 12 panel buildings located in Chongqing was selected to collect relevant environmental parameters, including the mean wind velocity ratio (MVR) for model validation. Different simulation scenarios were set to quantitatively analyze the wind condition improvement in both the lift-up layer and the target research area of the residence complex. Results show that the lift-up position at both ends or in the middle has the most significant effect—about 94.83% and 96.03%—on improving lift-up layer MVR. In addition, the target area MVR of the optimal condition is 36.35% higher than that of the basic condition and continues steady growth with the increasing lift-up ratio. Findings in this study provide scientific references for city planners to improve pedestrian-level wind comfort.

Shape optimization during design for improving outdoor wind comfort and solar radiation in cities

This paper delivers an idea of weather-based optimization as a sustainable design strategy addressing the changing climate. An environment-driven design technique is introduced and tested at the urban and architectural scale. Utilizing the interplay between the architectural intention and weather influences (specifically solar radiation and wind effects), the optimal design solution for the urban configuration and architectural shape emerges. An exploratory case study near the amphitheater in Kosice, Slovakia, demonstrates the proposed approach. Through the real-time iterative analysis of the environmental performance of multiple design variants, an urban concept of offices/apartment blocks, reacting to the local wind and sun situation, is formed. The wind flow situation and comfort are investigated in a design loop, blending the newly developed AI-driven simulation prediction models of InFraRed11InFraRed: AI-based real-time analysis of wind, sun, and thermal comfort in the streets developed by the CIL of the AIT in Vienna, Austria. and the sun hours analysis in Ladybug with the Galapagos optimization within Grasshopper. The final step of this method is the design and subsequent wind and sun analysis of fluid-shaped lamellae in three variants acting as wind catchers/shading systems. Improved pedestrian wind comfort for outdoor sitting (more than 30% increase in areas suitable for short and prolonged sitting) and optimum sunlight hours (25% gain in sunlight during winter solstice) is achieved using the proposed technique.

Integrating multiple models into computational fluid dynamics for fine three-dimensional simulation of urban waterfront wind environments: A case study in Hangzhou, China

A comfortable wind environment in urban waterfront area (UWA) is critical to improving the quality of life of surrounding residents and environment sustainability. In this study, the porous media model was combined with the water–air interface exchange model to conduct high-precision three-dimensional (3D) simulation of the ventilation environment at an urban waterfront. The results of this study indicate that the accuracy of the proposed model is as high as 95%. This model can be used to efficiently simulate urban ventilation and pedestrian wind environment comfort at different heights (1.5, 10, and 30 m) in a certain high-density 3D UWA. The order of ventilation potential of different types of urban areas is road space, green space, and river space. In summer, the pedestrian wind environment around the Gongshu section of the Beijing–Hangzhou Grand Canal was discovered to have low comfort at a height of 1.5 m. In winter, the wind comfort of the UWA on both sides of the canal is greatly affected by the direction of incoming wind, showing satisfactory ventilation performance when reaching heights of 10 and 30m. Accurate and efficient 3D simulation of urban ventilation is very helpful for adaptive planning and design of urban wind environment.

Fast wind prediction incorporated in urban city planning

Digital design and analysis tools are continually progressing, enabling more seamless integration of climatic impacts into the conceptual design stage, which naturally means enhanced environmental performance of the final designs. Planning sustainable urban configurations and, consequently, environment-derived architectural forms becomes more rapid and requires less effort enabling smooth incorporation into day-to-day practice. This research paper presents a wind prediction-based architectural design method for improving outdoor wind comfort through urbanism and architecture. The added value of the environment-driven design loop consisting of parametric design, wind flow analysis, and necessary design modifications lies in leveraging the newly developed wind prediction tool InFraRed. As is demonstrated in the application study in Kosice, Slovakia, iterating through various design options and evaluating their impact on the wind flow is swift and reliable. That enables the designer to explore the best-performing design alternatives for outdoor wind comfort, yet the extra time required for the analysis is negligible.

Evaluation of urban form influence on pedestrians' wind comfort

In recent decades, the pedestrian's outdoor thermal comfort has been critical for designing sustainable cities, which can be affected by wind flow in urban spaces. Urban forms influence wind speed, changing the urban air quality, and causing pedestrians' thermal comfort or discomfort. Therefore, it is required to design the urban spaces in such a way as to regulate the wind speed in order to provide thermal comfort situations for pedestrians based on their climate conditions. This study aimed to provide a framework for analysing the outdoor thermal comfort of various building layouts and their relation to wind speed in a site. This paper also proposed new indexes for improvements to the Physiological Equivalent Temperature (PET) index enabling the calculation of outdoor thermal comfort based on the likelihood of people being outside for a whole day. In-situ measurements were carried out in Tehran, Iran, to validate the presented framework. Simulations were conducted for 15 critical points in nine different building layouts for the windiest day on the site. ENVI-met was used to simulate the wind speed, outdoor air temperature, and mean radiant temperature, while PET was calculated by means of Leonardo and RayMan. The results demonstrated that pedestrians' outdoor thermal comfort for in-site and out-site points improved by 2.8% and 2.3%, respectively, compared to the current site situation. Also, the framework produced a suitable urban form to provide outdoor thermal comfort with evaluating different urban forms.

Application of a Wind Environment Simulation Generation Technology in Urban Planning

With the acceleration of urbanization, cities have shown a development trend of high density, high height, and high intensity, which significantly weakens the airflow in the city, resulting in the accumulation of heat and pollutants, and in the urban environment, the problem is getting worse. Therefore, it is particularly necessary to strengthen urban ventilation in the urban environment. However, in the real urban environment, the building layouts are diverse, the building forms are different, and the interaction of the building wind environment is complex due to the lack of relevant research on the complex building spatial form in the urban mesoscale area on the outdoor pedestrian. The research results are difficult to be applied in actual urban construction, and it is difficult to guide the optimization of the urban wind environment. To solve this problem, this paper adopts the CFD method in a real-scale (1 : 1) urban mesoscale regional wind environment simulation study. On this basis, the influencing factors of the urban pedestrian wind environment are analyzed, and the optimization strategy of the wind environment is proposed, which can provide practical guidance for the planning practice of enhancing urban wind comfort.

Pedestrian-level gust wind flow and comfort around a building array–Influencing assessment on the pocket park

• Wind flows around a building array and a row of trees are simulated and validated. • Mean and gust flow fields around building arrays with pocket parks are analyzed. • Pocket park amplifies PLW velocities under perpendicular inflow wind. • Pocket park promotes PLW comfort for sitting under oblique and parallel winds. Congested urban forms deteriorate urban ventilation, causing the problem of poor wind comfort at the pedestrian level. Pocket parks are small-scale open spaces for neighborhoods’ recreations, and they have the potential to alleviate this problem in cities, while this is rarely quantitatively investigated. This study investigates the pedestrian-level wind (PLW) flows around building arrays, and the influences of pocket park and vegetation on the mean and gust wind flows, and the wind comfort are further assessed. Steady-state Reynolds Averaged Navier-Stokes (RANS) simulations with the RNG k-ε model are used and validated with the benchmark experiments that give correlation coefficients above 0.80, including winds around a building array and trees. Results indicate that pocket park amplifies the mean and the gust flows in the streets under the perpendicular inflow wind, while attenuates the flows under the oblique and the parallel inflow winds. Inside the pocket park, an outdoor shelter space is created for pedestrian to relax and gather when winds in the streets are overly high. In this case, the vegetation promotes wind comfort for short-term sitting. These findings provide evidence for quantifying the effect of pocket parks with and without vegetation in achieving a healthy outdoor open space.

Pedestrian Wind Comfort Assessment Using Computational Fluid Dynamics Simulations With Varying Number of Wind Directions

The construction of a building inevitably changes the microclimate in its vicinity. Many city authorities request comprehensive wind studies before granting a building permit, which can be obtained through Computational Fluid Dynamics (CFD) simulations. Investigating the wind conditions for 12 wind directions has previously been considered sufficient in most literature and the industry. However, the effect of changing the number of simulated wind directions is still not well understood. This article investigates the influence of the number of simulated wind directions on pedestrian wind comfort maps. A neighborhood in Niigata city, Japan, was chosen as a case study. Simulations are performed in OpenFOAM using a Reynolds-averaged Navier-Stokes model and the realizable k-ϵ turbulence model. The inlet profiles form a homogeneous atmospheric boundary layer with neutral stratified conditions and a logarithmic velocity profile. The pedestrian wind comfort maps are converging toward a final map as more wind directions are included. The area of the maps classified with the same comfort as using 64 wind directions is 79% using 4 wind directions, 92% using 8 wind directions, 96% using 16 wind directions, and 99% using 32 wind directions. A greater understanding of the influence of the number of simulated wind directions included may enable more efficient pedestrian wind comfort studies that recognize the associated uncertainties.

Numerical evaluation of pedestrian-level wind and indoor thermal comfort of a historical monument, Muğla, Turkey

PurposeThe study aims to analyze both thermal and wind comfort conditions of a historical mosque's interior and outdoor spaces for the planning of further conservation decisions.Design/methodology/approachThe method is composed of two steps. First, thermal comfort analyses are conducted via Design-Builder Software. The predicted mean vote (PMV) and predicted percentage of dissatisfied indices were calculated and evaluated using the ASHRAE 55–2010 standard. Thermal comfort conditions are analyzed with the proposed three operations. Second, wind comfort analyses are conducted via computational fluid dynamics (CFD) software. Outdoor thermal comfort conditions are predicted by air temperature, mean radiant temperature, wind speed and relative humidity.FindingsThe (PMV) in the harim was calculated as −1.83 (cool) which corresponds to a predicted percentage of dissatisfaction (PPD) equal to 68.54%. Thermal comfort was provided by daytime and continuous operations; however, intermittent operations did not provide thermal comfort. The wind velocities around the mosque are well below the 5 m/s limit value for standing defined by NEN 8100 wind nuisance standard. Moreover, the limit value of 2.5 m/s for sitting was also satisfied with more than 80% of the semi-enclosed area around the entrance of the mosque. Last comer's hall remains in a slight cold stress range, the rest of the areas have no thermal stress.Originality/valueThis two-stage study creates a base for further improvements to provide comfort conditions in a historical building without interfering with its original features.

Pedestrian Wind Analysis for Indian Sub-Continent

Urbanization in India is causing local wind and climate changes near high-rise buildings, affecting the urban wind climate pedestrian-level winds to dangerous and uncomfortable levels. Hence, today's architectural planning Wind comfort has to not only consider the wind load and internal conditions, but also must consider the outdoor wind building design environment. This study reviewed the methods of evaluating pedestrian-level wind weather, different Wind tunnel test standards of wind comfort, and various techniques for evaluating pedestrian-level wind speed. In the CFD Numerical following section, a brief overview of the current research on this topic and the way forward in India is Modeling related to the design and configuration of windward buildings at the pedestrian level. After analysing the previous documents, the authors recommend it is very necessary to homogenize the various wind standards, as it might have different consequences for planers. Among the various wind tunnel experimental technologies, compared to the hot wire wind speed measurement method, the Irwin probe’s accuracy and simplicity is justified, and can be installed in multiple positions to measure wind speed horizontal of pedestrians at the same time. For the numerical simulation, several researchers have used the Renault medium Navier stokes-based technique, although the precision of this technique is not as good as the simulation of large eddies and the simulation of separate eddies. However, this technology is not only precise but also costs less due to its requirement of less computing resources.

Outdoor Wind Comfort and Adaptation in a Cold Region

The outdoor wind comfort is important for evaluations of the urban wind environment. The existing wind comfort criteria are based on the correlations between wind parameters, human activity levels, and wind comfort level categories. These criteria vary among different climates and regions, and they are influenced by meteorological parameters and human wind adaptation. In this study, an outdoor wind comfort questionnaire survey was conducted and meteorological measurements were collected in Xi’an, which is located in the cold region of China. The square and lake side were chosen as the test sites. The mean wind sensation vote (MWSV) and wind speed of neutral wind sensation were used as indexes to analyze the correlation between outdoor wind comfort and human wind adaptation. The results showed that the wind sensation level was generally moderate. At −1 < MWSV < 1, the fluctuations in the wind speed had little effect on the wind sensation, but when MWSV > 1 or MWSV < −1, the degree of discomfort increased as the absolute value of MWSV increased. When the wind speed exceeded 1 m/s, the amount of clothing insulation was greatly increased. The metabolic rate fluctuated between 1.5 met and 2 met. Expectations that the wind speed in the winter would be less than 1.05 m/s were greater than expectations that the wind speed would be more than 1.05 m/s in the summer, and people generally adapted to a low wind environment with wind speeds below 1 m/s. The acceptable wind ranges for more than 90% of participants at the square and lake side were (0 m/s, 2.02 m/s) and (0.01 m/s, 2.86 m/s). This study provides support for the revision of outdoor wind comfort standards and a methodological basis for outdoor wind comfort research at the same latitude throughout the world.

CFD Analysis of Wind Distribution around Buildings in Low-Density Urban Community

The computational fluid dynamics (CFDs) models based on the steady Reynolds-averaged Navier–Stokes equations (RANSs) using the k−ω two-equation turbulence model are considered in order to estimate the wind flow distribution around buildings. The present investigation developed a micro-scale city model with building details for the Hail area (Saudi Arabia) using ANSYS FLUENT software. Based on data from the region’s meteorological stations, the effect of wind speed (from 2 to 8 m/s) and wind direction (north, east, west, and south) was simulated. This study allows us to identify areas without wind comfort such as the corner of the building and the zones between adjacent buildings, which make this zone not recommended for placement of restaurants, pedestrian passages, or gardens. Particular attention was also paid to the highest building (Hail Tower, 67 m) in order to estimate, along the tower height, the wind speed effect on the turbulence intensity, the turbulent kinetic energy (TKE), the friction coefficient, and the dynamic pressure.

Integrated BIM and VR for Interactive Aerodynamic Design and Wind Comfort Analysis of Modular Buildings

Modular building is becoming a common sight due to government policies promoting greater automation and productivity. When moving towards modularity, indoor comfort within volumetric modules, such as levels of humidity and temperature, natural ventilation, and air pollutant transport, have a major effect on human health and well-being. Computational fluid dynamics simulations (CFD) are used to evaluate the efficiency of natural ventilation. However, designers usually find it difficult to visualize the CFD simulation results, which can deepen users’ understanding of the wind environment and help optimize the design of modular buildings. To overcome this challenge, this paper presents an integrated approach based on building information modeling (BIM) and virtual reality (VR), with the aim of analyzing the aerodynamic design and wind comfort for modular buildings. The framework consists of four salient components. First, a new method, combining OpenStreetMap and Dynamo, is proposed to achieve rapid urban modeling of modular buildings. The second step involves the use of CFD to simulate the outdoor wind environment surrounding modular buildings. The third step emphasizes the integration of CFD-computed data with VR applications to create an immersive virtual environment for designers to analyze the wind environment of design alternates. Finally, the visual experience of non-professional users is used to improve the ventilation of the building and support more informed decision marking at the early stage of building design. The proposed framework is illustrated via a case study that focuses on a group of modular housings in the urban area of Singapore. The results indicate that visualization of CFD simulations in VR provides designers with more details regarding the actual space, and it is expected to help optimize the architectural design.

Evaluation of urban planning methods toward bioclimatic and resilient urban spaces

Open urban spaces play a key role in achieving city resilience, the urban ability to survive in extreme conditions caused by phenomena such as heat waves and urban heat islands and to absorb change and disruption. Urban regeneration planning and intervention design are critical for providing thermal and wind comfort to citizens and enhancing urban resilience. Supporting decision makers, the microclimate created in urban planning use cases is simulated to identify, assess, and rate the bioclimatic impacts of alternative plans. The Bioclimatic Index is proposed based on the simulation results and the rated plans to strengthen evaluation of urban regeneration plans and interventions that empower urban microclimate and resilience. The methodology is applied to an abandoned space in the Old Port of Patras, Greece, of wet Mediterranean climate, and can be extended to urban areas with similar characteristics.

Data Generative Machine Learning Model for the Assessment of Outdoor Thermal and Wind Comfort in a Northern Urban Environment

Data Generative Machine Learning Model for the Assessment of Outdoor Thermal and Wind Comfort in a Northern Urban Environment

Investigating the Effects of Urban Sidewalk Walls on Pedestrian Level Wind Comfort (Case Study: Tabriz City)

Investigating the Effects of Urban Sidewalk Walls on Pedestrian Level Wind Comfort (Case Study: Tabriz City)

Wind adaptive urban seafront buildings design for improving urban ventilation and pedestrian wind comfort in Mediterranean climate

Coastal cities in the Mediterranean region have cool sea breezes that can reduce the effects of global warming, urban heat islands (UHI), and air pollution. However, in many coastal cities, impermeable urban seafront buildings prevent cool sea breezes from penetrating the city while at the same time posing a risk of pedestrian wind discomfort. This study aims to design wind-adaptive urban seafront buildings that improve urban ventilation and pedestrian wind comfort in Izmir, a high-density Mediterranean city, using the parametric design and computational fluid dynamics (CFD) method. Alternative seafront buildings consisting of two-rows and shifted configurations were designed using the two proposed urban geometric indicators. The authors found that the denser and more compact seafront building configuration can prevent the risk of wind discomfort and achieves the highest ventilation efficiency (82%). The findings apply to similar coastal urban environments and help urban policymakers and designers.

Comparing the Role of High-Rise Building Form in Improving Pedestrian Wind Comfort Andreducing Wind Velocity by CFD Simulation

Comparing the Role of High-Rise Building Form in Improving Pedestrian Wind Comfort Andreducing Wind Velocity by CFD Simulation