Search Results (163)

Outdoor sports spaces in residential areas must provide safe and comfortable conditions for daily exercise, yet in severe cold regions their use is constrained by wind, solar exposure, thermal stress, noise, and air quality. Using six sites in Harbin, China, this study developed an Analytic Hierarchy Process (AHP)-based evaluation system covering the wind, light, acoustic, thermal, and air environments. Candidate indicators were screened using a user questionnaire, expert AHP judgments were used to derive weights, and site performance was quantified through field monitoring, site surveys, and ENVI-met simulation. The indicator weights, in descending order, were wet-bulb globe temperature (14.96%), pedestrian-level wind speed (13.67%), building layout conducive to air circulation (13.55%), pedestrian-level wind vortices and still-air zones (12.79%), sunlight exposure and lighting effectiveness (12.67%), shading rate of hard ground surfaces and structures (12.15%), reflectivity of pavement and covering materials (11.37%), and outdoor noise level (8.83%). Overall scores differed across the six sites. An AHP-weighted performance-shortfall analysis, calculated relative to the ideal Grade 5, identified outdoor noise, shading, building-layout-related air circulation, and sunlight/lighting performance as the four largest cross-site improvement needs. The resulting framework supports the diagnosis and renewal of outdoor sports spaces in cold-region residential areas. The empirical results represent the monitored summer and autumn transitional scenarios rather than year-round performance. Full article

Outdoor pedestrian wind comfort and indoor natural ventilation are important aspects of wind environment performance in high-rise residential developments. However, the two objectives are evaluated in different spatial domains and may exhibit inconsistent responses to changes in design parameters. Identifying solutions that balance both objectives through conventional trial-and-error design becomes increasingly difficult as the number of variables and candidate combinations increases. This study develops a multi-objective optimization method that integrates parametric modeling, computational fluid dynamics (CFD), and a hybrid NSGA-II–MOPSO algorithm to coordinate outdoor and indoor wind performance. Building positions, orientations, and window locations are represented by a 13-dimensional design vector. Outdoor pedestrian wind comfort and indoor natural ventilation are quantified using two objective functions, DCTC_out and DCTC_in, defined as the ratios of evaluation points outside the prescribed comfort ranges to those within them. Indoor simulations use façade pressures obtained from the outdoor CFD calculations as boundary inputs. The method is applied to a planned high-rise residential development in Chongqing, China. The optimization used a population of 25 candidate designs over 50 generations, yielding 1250 CFD-evaluated designs. The population mean values of DCTC_out and DCTC_in decreased by 16.25% and 17.62%, respectively, while their best-so-far values reached 2.14888 and 0.52469. Nine solutions remained on the final first non-dominated front, representing different trade-offs between outdoor and indoor performance. Compared with the outdoor-priority solution, the compromise solution increased DCTC_out by only 3.81% while reducing DCTC_in by 22.81%. Further improvement in indoor performance was accompanied by a substantially greater deterioration in outdoor performance. The results support the joint consideration of residential layout and opening design when outdoor and indoor wind performance are evaluated simultaneously. Full article

Urban walking spaces are shaped by both relatively stable visual–spatial features and dynamic contextual exposures, yet the independent emotional effects of these exposures remain unclear. This study develops a causal screening framework to examine the adjusted effects of high pedestrian flow and high background wind speed on pedestrian emotion. Using 9552 participant-location observations collected along a 1.0 km walking route in Changsha, China, pedestrian emotion was expressed as a baseline-referenced emotional response (BRER). Propensity-score trimming established treatment-specific overlap before applying partially linear regression, double machine learning, and causal forest estimation. High flow showed a stable negative adjusted effect with broader empirical support and some heterogeneity, whereas high wind also showed a negative estimate but was treated as exploratory because of limited independent exposure support. Overall, dynamic social and meteorological exposures may retain adjusted effects on pedestrian emotion beyond the observed visual–spatial environment, with stronger evidence for pedestrian flow. Urban walking-space design should therefore strengthen its capacity to buffer transient social and meteorological pressures. Full article

Courtyard-cluster layouts are common in rural public buildings in hot-humid regions, but their open-space types remain poorly quantified. We assessed a completed elderly-care center in Shaoguan, South China, using steady-state RANS CFD (simpleFoam, standard k–ε, OpenFOAM 8), porous-media vegetation, Solar Cal-based mean radiant temperature (MRT), and pedestrian-level Universal Thermal Climate Index (UTCI). Published component-level validation was used to assess toolchain reliability. Simulations represented peak heat stress at noon on 24 July (air temperature 30.3 °C, relative humidity 69%, southwesterly wind 2.9 m/s). Relative to an unobstructed reference (MRT 60.1 °C; UTCI 40.0 °C), architectural open spaces reduced mean MRT by 21.2 °C (35%) and UTCI by 5.3 °C (13%). Covered, laterally open grey spaces were coolest (mean MRT 34.63 °C; UTCI 33.61 °C), whereas open courtyards were warmer (41.79 °C; 35.34 °C) but 18% better ventilated (0.87 versus 0.74 m/s) and served as ventilation nodes. With uniform air temperature and humidity, UTCI variation was strongly associated with MRT (R = 0.989) and weakly with wind speed (R = −0.182). These scenario-bounded results support a shade-first strategy in which courtyards supply ventilation to adjacent covered spaces. Full article

University dormitories in cold climate regions face the dual challenges of high heating energy consumption and poor outdoor pedestrian comfort during winter. Existing studies on university dormitories have primarily focused on individual building performance optimization, while insufficient attention has been paid to the optimization of dormitory cluster layouts and their multi-objective performance. To address this gap, this study establishes a parametric multi-objective optimization framework to simultaneously minimize building energy use intensity, minimize wind speed at pedestrian height, and maximize outdoor thermal comfort. Based on three floor area ratio scenarios, 24 dormitory prototypes are extracted from three building typologies: row-type buildings, detached buildings, and enclosed buildings. The optimization process was implemented on the Grasshopper platform using the NSGA-II algorithm. Cluster analysis is conducted on the Pareto front, and Pearson correlation analysis is applied to investigate the relationships between six urban morphological parameters and the three optimization objectives. The results indicate that: (1) enclosed buildings (E-1 type) and detached buildings (D-1 type) dominate the Pareto-optimal solution set; (2) high-FAR buildings are predominantly distributed in the northeastern part of the site, while public spaces are concentrated in the central-southern area; (3) correlation analysis indicates that shape coefficient (SC) exhibits the strongest correlations with the three objectives; and (4) compared with dominated solutions, Pareto-optimal solutions reduce WS by 10.46% and EUI by 6.57%, while improving UTCI by 0.05 °C. This study provides quantitative decision-making support for efficient planning and low-carbon design of university dormitory clusters in cold climate regions. Full article

Vortex-induced vibration (VIV) poses a significant serviceability concern for wide streamlined box girders of long-span suspension bridges. This study investigates the VIV performance and aerodynamic mitigation of a wide streamlined box girder with a width-to-depth ratio (B/D) of approximately 10 through sectional model wind tunnel testing. The original cross-section was found to exhibit pronounced heaving and torsional VIV at positive wind angles of attack, with amplitudes considerably exceeding the prescribed serviceability limits. A systematic experimental investigation was conducted to evaluate the influence of three geometric parameters, i.e., wind fairing inclination angle, inspection rail position, and pedestrian railing porosity and panel arrangement, on VIV performance. Experimental results demonstrate that reducing the wind fairing inclination angle from 65° to 45° is the most effective mitigation measure. An appropriate porosity of the pedestrian railing is shown to substantially improve VIV performance. Furthermore, under equivalent overall porosity, a uniformly distributed alternation of solid and ventilated panels yields markedly superior VIV suppression compared with continuously sealed arrangements. Subsequent flutter and aerostatic wind tunnel tests confirm that the recommended cross-section preserves the favorable flutter stability and aerostatic performance of the original design. Strouhal number analysis reveals that the VIV lock-in is governed by St ≈ 0.12. Notably, the St number obtained from the pitching moment coefficient is nearly twice that obtained from the lift coefficient. Full article

Commercial plots in hot–humid tropical island cities require effective pedestrian-level ventilation; however, the extent to which different layout forms enhance wind-driven cooling potential under fixed development intensity remains insufficiently quantified. Taking Haikou as a representative tropical island case, this study examines how building count and spatial enclosure form affect the pedestrian-level wind environment of a commercial plot. A total of 63 layouts with one, two, and three building units were constructed under identical development constraints. ANSYS Fluent 2023 R1 (ANSYS, Inc., Canonsburg, PA, USA). was used to simulate pedestrian-level wind fields under representative summer southerly and east–northeasterly (ENE) wind conditions. Six ventilation-related indicators, including area-weighted mean wind speed, maximum wind speed, and the non-low-wind-speed area ratio in both seasons, were integrated into a Wind-Driven Cooling Potential Index (WDCPI). The weighting scheme combined climate-informed seasonal weights with entropy-based objective indicator weights. The results show that summer ventilation is more sensitive to layout form than winter ventilation. Although the average WDCPI decreases as building subdivision increases, layout B2 shows the highest WDCPI among the tested scenarios because its open inter-building space forms a continuous ventilation path aligned with the prevailing summer wind. The sensitivity analysis supports the relative stability of the ranking results. These findings highlight airflow connectivity and windward openness as important layout-screening principles for cooling-oriented commercial plot design in tropical island cities. Full article

Wind–Rain Bridge architecture is an important type of ancient bridge architecture. To reveal the factors contributing to the decline in the spatial performance of Wind-Rain Bridges in Hunan under the influence of urbanization and to assess their spatial legibility across different urbanization gradients, this study addresses the limitations of traditional research, which has largely relied on static observations and lacked quantitative analysis. The findings provide a scientific basis for the refined conservation and adaptive revitalization of traditional architecture. This study examines 535 Wind–Rain Bridges in Hunan. Using Space Syntax, core indicators such as Integration and Choice were quantitatively calculated for both Wind–Rain Bridges and modern bridges. A controlled variable experiment was further employed to analyze the disturbance effects of modern road networks. In addition, an XGBoost multi-classification model was constructed to assess spatial legibility levels and identify key spatial-topological predictors. The results indicate that the decline in the spatial performance of Wind–Rain Bridges in Hunan is not linearly correlated with urbanization. Urban-type Wind–Rain Bridges are most significantly affected by the replacement effect of modern road networks, whereas Semi-Village-type Wind–Rain Bridges exhibit the strongest resilience. Among the variables included in this study, Integration and Mean Depth are the strongest predictors of spatial legibility. This study establishes an analytical framework of “type classification–factor identification–differentiated strategy formulation” and confirms that the primary driver of the spatial performance decline of Wind–Rain Bridges in Hunan is the fragmentation of traditional pedestrian road networks caused by modern transportation systems under urbanization, rather than the aging of the bridge structures themselves. Full article

In coastal residential areas, the combined effects of high temperature, high humidity, and weak wind conditions during summer intensify outdoor heat exposure and reduce pedestrian thermal comfort. To investigate the influence mechanisms of tree height and spatial layout on pedestrian-level thermal comfort, this study selected a typical residential community in Chengyang District, Qingdao, as the research site. Based on field meteorological observations, an ENVI-met model was established and validated. Using the existing composite greening scenario as the baseline, three tree layout types (row, cluster, and free layouts) and four height scenarios (4 m, 6 m, 8 m, and 10 m) were configured to quantitatively compare variations in physiological equivalent temperature (PET) under different planting schemes. The results indicate that tree configuration significantly affects summer thermal comfort. Its regulatory mechanism is governed not only by air temperature reduction but also by shortwave radiation interception, longwave radiation accumulation, and shading continuity. Although low-to-medium height trees can reduce local air temperature through transpiration, their limited canopy height and shading continuity restrict their ability to effectively attenuate direct shortwave radiation at pedestrian level, and in some cases may even increase mean radiant temperature (Tmrt) and PET. In contrast, 10 m tall trees arranged in row and cluster layouts can form continuous shaded cores, with the 10 m cluster layout demonstrating the best overall performance by significantly reducing Tmrt and PET. The free layout, characterized by dispersed canopies and fragmented shading, provides relatively limited thermal comfort improvement. The findings suggest that residential greening optimization should strengthen the coordination between tree height, canopy structure, and activity spaces. Tall trees should be prioritized in children’s play areas, elderly resting areas, residential entrances, main pedestrian pathways, and west-facing sun-exposed zones, while integrating building shadows and road orientation to create a continuous yet not overly enclosed shading network, thereby enhancing summer thermal adaptability in residential areas. Full article

Public spaces in cold-region historic districts often contain a mismatch between spatial accessibility and winter environmental usability. Highly accessible streets may be exposed to strong winter winds, whereas sheltered spaces may remain underused because of weak network connectivity. Taking the Xinmin Street historic district in Changchun, China, as a case study, this study develops a coupled analytical framework that integrates space syntax, ENVI-met microclimate simulation, and GIS-based overlay analysis to identify winter public-space potential under heritage conservation constraints. Visual integration derived from Depthmap was used to represent configurational accessibility, while pedestrian-level wind speed at 1.5 m was used to characterize winter wind exposure under a representative clear winter-day scenario. The results show that high-integration areas are concentrated along the main north–south street, but several of these segments coincide with wind corridors and therefore show limited winter usability. Conversely, low-wind areas are mainly located on the leeward sides of buildings and within relatively enclosed spaces, although some lack sufficient pedestrian connectivity. Low-intervention optimization, including link completion, entrance adjustment, permeability enhancement, and winter-priority route organization, increased the average integration value of low-wind spaces from 7.41 to 8.82. The framework helps planners and conservation authorities identify sheltered but under-connected spaces and supports heritage-sensitive renewal strategies for improving winter public-space usability in cold-region historic districts. Full article

With the acceleration of urbanization and the intensification of climate change, wind conditions have become a critical factor in architectural design. They not only affect a building’s wind resistance but also influence ventilation, pollutant dispersion, pedestrian comfort, and energy consumption. Traditional computational fluid dynamics (CFD) simulations are costly. Although the application of machine learning for CFD prediction has become a relatively mature technology, machine learning models still face challenges in actual architectural design workflows. Building upon recent advancements in the field, it proposes two core technologies: a method for predicting outdoor wind environments in buildings based on the Site-Specific Training for Design Tasks (SST-DT) strategy, and an automated machine learning workflow. These innovations improve upon existing wind environment analysis methods and systems, establishing a fully automated working framework that is easy for architects to learn and use. Within this framework, dataset acquisition and model training are performed automatically. Finally, this framework was validated across various prediction tasks with different objectives. It significantly lowers the barrier to entry for architects adopting machine learning, advances the performance-driven design paradigm, and facilitates the deep integration of machine learning technologies into architectural wind engineering. Full article

To address the mismatch between spatial form and wind environment of residential districts in cold-region valley-type cities, which leads to poor thermal comfort, low ventilation efficiency and high building energy consumption, this study takes Hongyun Runyuan, a typical large-scale residential district in Lanzhou, as the research case. Using orthogonal experimental design, nine spatial schemes were developed with three core morphological parameters (building orientation, spacing coefficient, enclosure degree), each set with three levels. CFD simulations via PHOENICS were performed to analyze the influence weight of each parameter on the winter wind environment at 1.5 m pedestrian height. Results show that building orientation exerts an extremely significant effect on the winter wind environment (p = 0.006), while the spacing coefficient and enclosure degree have no significant independent effects (all p > 0.05). The optimal scheme, featuring 10° east of south orientation, 1.1 spacing coefficient and 0.3 enclosure degree, can effectively meet the winter wind protection demand. The quantitative optimization strategies proposed in this study provide scientific support for wind-friendly residential planning and building energy efficiency improvement in cold-region valley-type cities. Full article

Against the backdrop of global warming and rapid urbanization, high-density central urban areas in valley cities face exacerbated ventilation deterioration and reduced pedestrian-level wind comfort due to topographic constraints and intensive development. This study investigates the coupling mechanism between spatial morphology and wind environment in Lanzhou’s Xiguan Cross area using a complex network model, CFD numerical simulation, and statistical analysis. A ventilation resistance surface was constructed using circuit theory and ArcGIS 10.8 to identify ventilation corridors. PHOENICS was used to simulate summer pedestrian-level (1.5 m) wind fields, while SPSS 2025 was employed for regression analysis of building density, enclosure degree, and dispersion degree against the mean wind velocity ratio. Results indicate: (1) wind velocities are higher at the periphery and lower in the interior; (2) building density and enclosure degree have a highly significant negative impact on the wind velocity ratio, whereas dispersion degree has a significant positive impact, with influence intensity ranked as enclosure degree > building density > dispersion degree. Based on these findings, three differentiated morphological optimization strategies are proposed and validated through simulation, effectively increasing the proportion of comfortable wind zones. This study provides a scientific basis for improving urban microclimate and pedestrian comfort through urban design. Full article

The development of metro-led urban underground public spaces (UUPSs) provides urban residents with extensive pedestrian-friendly activity areas sheltered from rain, snow, strong winds, and other extreme weather conditions. Although an increasing number of people are engaging in daily commercial and leisure activities within UUPSs, problems such as inconvenient transfer, poor visibility, and a lack of natural light, which indicate poor environmental quality, have led to an uneven distribution of user behavior, thereby reducing the efficiency of space utilization. Our aim in this study was to predict UUPS utilization rates by investigating the relationship between UUPS environmental attributes and user behavior characteristics and preferences. Six typical UUPSs in Wuhan were selected as case studies. User behavior data were collected using panoramic camera recordings, on-site observations, and space syntax methods, while spatial environmental factors were quantified. The correlation between various factors and multi-dimensional user behavior characteristics was discussed, and a Random Forest model was established to predict behavioral preferences. Our results indicate that accessibility and visibility are fundamental factors influencing user behavior characteristics, while the impact of landscape elements is relatively low. Regarding behavioral preference prediction, UUPS environmental features achieved the highest prediction accuracy for leisure behaviors, whereas the predictive performance for sports activities was lower. In this study, we reveal the influence of UUPS environmental factors on user behavior characteristics and predict preference patterns of different behaviors for space types. Focusing on the behavioral needs of space users, we provide a reference for the subsequent human-centered design of UUPSs. Full article

Mitigating heat stress in high-density historical districts remains a critical challenge in urban renewal due to complex morphological heterogeneity. Existing research often relies on isolated intervention measures, lacking systematic, multi-strategy assessments driven by high-precision spatial data. This study addresses this gap by establishing a quantitative framework that couples thermal infrared remote sensing with Computational Fluid Dynamics (CFD) to optimize microclimate responses in Beijing’s Liulichang Historic District. Remote sensing data were utilized to retrieve high-resolution Land Surface Temperature (LST), providing accurate thermal boundary conditions for micro-scale wind-thermal simulations. A baseline scenario (S0) and seven renewal strategies (S1–S7)—integrating varying configurations of greenery, water bodies, and permeable pavements—were evaluated using pedestrian-level comfort indices. Results reveal that single-factor interventions yield marginal improvements or thermodynamic trade-offs; specifically, adding greenery (S1) in narrow street canyons increased aerodynamic roughness, thereby obstructing ventilation and inducing localized warming. Conversely, composite strategies significantly enhanced microclimatic quality. The “greenery-water-permeable pavement” strategy (S4) achieved optimal synergistic effects, characterized by substantial cooling and spatial homogenization. Regression analysis identified water bodies as the dominant cooling driver, where a 10% increase in water coverage resulted in a temperature reduction of approximately 5.17 °C. Conversely, greenery alone showed no statistically significant cooling contribution (p > 0.05) without the synergistic presence of water or pavement modifications. This research suggests that urban renewal in high-temperature zones (>36 °C) should prioritize composite cooling networks. Furthermore, vegetation layouts near wind corridors must be precisely regulated to prevent ventilation degradation. These findings provide a scientific basis for the climate-adaptive sustainable regeneration of culturally significant, high-density urban blocks. Full article