Research on the Optimization of Healthy Living Environments in Liyuan Block Empowered by CFD Technology: A Case Study of the Liyuan Block in Dabaodao, Qingdao

Abstract

In the process of revitalizing historic districts, creating a healthy living environment requires a focus on the microclimate comfort of historic districts. Microclimate comfort refers to the comprehensive physiological perception and psychological satisfaction of climate elements such as heat, wind, and humidity under specific local environmental conditions, typically within a spatial range of horizontal scale < 100 m and vertical scale < 10 m. Among these, wind environment quality, as a key factor influencing pedestrian health experiences and cultural tourism appeal, holds particular research value. This study takes the Dabao Island Courtyard District in Qingdao as its subject, employing computational fluid dynamics (CFD) simulation methods from the artificial intelligence (AI) technology framework for modeling. CFD is a numerical method based on computer simulation, which solves fluid control equations (such as the Navier–Stokes equations) through iterative optimization to achieve high-fidelity simulation of physical environments such as airflow, turbulence, and heat transfer. A three-dimensional geometric model of the Dabao Island courtyard district was established, and boundary conditions were set based on local meteorological data. Numerical simulations were conducted to analyze the wind environment before and after the renovation of different layouts, functional spaces, and spatial scales (individual courtyards, clustered courtyards, and surrounding neighborhoods) of the courtyard district. The results indicate that factors such as building layout, street orientation, and renovation strategies significantly influence the wind environment of the Dabao Island neighborhood courtyards, thereby affecting residents’ perceptions of wind comfort. For example, unreasonable building layouts can lead to excessive local wind speeds or vortex phenomena, reducing wind comfort, whereas reasonable renovation and update strategies can facilitate the introduction of wind corridors into the historical courtyard buildings, improving wind environment quality. This study contributes to better protection and utilization of traditional neighborhoods during urban renewal processes, creating a more comfortable wind environment for residents, providing scientific decision-making support for the renovation of historical neighborhoods under the Healthy China strategy, and offering methodological references for wind environment research in other similar traditional neighborhoods.

1. Introduction

Against the dual backdrop of the Healthy China Initiative and urban renewal initiatives, there has been a growing emphasis on the quality of historical district environments. The microclimate quality of historical districts has become a key indicator of the health performance of the human living environment [1]. As a crucial component of the microclimate, wind conditions directly influence pedestrian comfort [2,3,4], health outcomes, and the city’s ecological environment [5]. A good wind environment accelerates the dissipation of sensible heat through efficient ventilation and enhances the potential for ventilation-induced cooling, which is crucial for mitigating the urban heat island effect in summer and promoting the dilution and transport of atmospheric pollutants [6,7]. This, in turn, is deeply intertwined with residents’ respiratory health, the quality of outdoor activities [8], and the ecological sustainability of neighborhoods [9]. Optimizing the wind environment in outdoor gathering spaces has a positive impact on alleviating ventilation-dependent diseases such as asthma and allergic conditions [10]. A stable laminar flow in an ideal summer wind environment effectively prevents stagnant airflow and the accumulation of potential pathogens. Good design can ensure orderly airflow around the space, using natural ventilation to prevent the buildup of pollutants and reduce the concentration of allergens such as pollen, dust mites, viral aerosols, and PM2.5 in the air. This enhances the efficiency of directed pollutant removal, thereby mitigating the risk of respiratory diseases.

Numerous studies have confirmed that the morphological characteristics of traditional courtyard buildings significantly influence their outdoor wind environment. Courtyards, as enclosed or semi-enclosed spaces open to the sky and surrounded by buildings or walls (common forms include U-shaped, L-shaped, etc.), have key morphological parameters, including courtyard plan shape [11,12,13], building enclosure height [14,15,16,17,18], building orientation [19], key spatial proportions of the courtyard (such as aspect ratio) [20], location of door openings [21], application of shading facilities [22,23], and internal vegetation layout [24,25], directly shape internal airflow patterns (such as vortex structures and ventilation efficiency) and local wind speed distributions [26], thereby significantly influencing pedestrian wind comfort. The aforementioned wind environment characteristics at the courtyard scale form the microscopic foundation of the overall wind environment pattern in urban neighborhoods and are closely coupled with pollutant dispersion and sensible heat dissipation processes at the neighborhood and larger scales [27].

Previous studies have primarily been limited by the following shortcomings: they have overlooked the dynamic adjustments made to social and cultural strategies and climate adaptability, which have led to changes in wind environment comfort within the microclimate of historic districts. The Dabao Island Courtyard District in Qingdao serves as a typical example of traditional courtyard architecture in northern China [28]. Its nested, enclosed courtyard spaces serve as carriers of deep historical memories. For the Dabao Island Courtyard District, its unique architectural layout, scale, and spatial form differ significantly from modern buildings. The wind environment of the Dabao Island courtyard district is influenced by a combination of factors, including architectural layout [29,30], street orientation [31,32], renovation strategies [33], and surrounding topography [34,35]. These factors interact to form a complex wind field, which in turn affects residents’ wind comfort. While these courtyards have persisted and evolved over the long course of history, they now face new challenges in terms of modern urban climate adaptability. Currently, although there is growing interest in healthy microclimate design, few studies have used advanced simulation tools to conduct quantitative and spatially detailed assessments of wind environments in historical urban settings. Based on this, this study employs computational fluid dynamics (CFD) technology, supported by artificial intelligence-driven modeling tools, to simulate wind flow patterns at high spatial resolution. It constructs a wind environment simulation system for traditional neighborhoods, conducting in-depth research and comparisons of wind environments in courtyard neighborhoods before and after renovation strategies, as well as the coupled relationships between wind environments within courtyards and pollutant dispersion and sensible heat dissipation processes surrounding courtyard neighborhoods before and after renovation strategies, as well as the coupled relationship between wind environment within courtyards and pollutant dispersion and sensible heat dissipation processes. This research explores the intrinsic mechanisms linking historical spatial forms to healthy living environments, adapting to the architectural complexity of traditional areas. It provides empirical evidence for healthy living design based on historical wisdom and climate responsiveness. This not only enhances the microclimate quality of the Da Bao Island historical district and improves residents’ quality of life, but also offers scientific planning strategies for optimizing microclimate quality and achieving sustainable protection and renewal of traditional districts.

2. Materials and Methods

2.1. Research Methods

CFD simulation software is widely used in the assessment of courtyard wind environments [36]. Research on wind environments in traditional historic districts typically evaluates the wind environment of a district based on two different wind directions in winter and summer. Generally, these studies combine airflow characteristics with wind comfort standards and local wind statistics to assess wind comfort. In this study, a CFD simulation approach is used to assess and study the wind environment of the Liyuan in the historical district of Dabaodao, Qingdao, employing LES (Large Eddy Simulation) to simulate the air flow field conditions. The corresponding control equations and a turbulence model were established based on fundamental physical laws such as mass conservation, momentum conservation, and energy conservation. The computational domain size was set to 100 m, with a boundary condition computational domain model range of 100 m, a calculation domain resolution of 0.3 m, an inlet turbulence intensity of 10%, and a reference height of 1.5 m, which determined the simulation’s spatial range. Both wind direction and reference wind speed were based on local meteorological data from Qingdao. Based on the simulation trial calculation, the number of iterations was 255. The research framework of this study is depicted in Figure 1.

2.2. Ideal Model

The main characteristics of the Liyuan neighborhood are its wall-less urban community formed by the enclosure of primary and secondary urban roads, and the division of small and medium-sized streets into groups. The community has a high road network density, with narrow roads and a dense road network, and the seamless connection between community space and urban space is the main spatial characteristic of the Liyuan neighborhood. The organic combination of public spaces open to the outside and spaces for internal residential or commercial use is the main functional characteristic of the courtyard neighborhood.

The selected architectural models are representative of the spatial form and building layout observed in the courtyard district survey. A single courtyard is defined as a building that is separated by small and medium-sized streets and serves as the only enclosing structure separating the public space of the street from the private courtyard. A courtyard cluster is defined as a group of buildings separated by small and medium-sized streets. A courtyard neighborhood is defined as an area enclosed and separated by the city’s main and secondary roads. According to the three different spatial scales—single courtyards, courtyard clusters, and surrounding neighborhoods—separate models were established for courtyard buildings and courtyard neighborhoods (Figure 2). For single-building structures, only the main building portion enclosed by the street and courtyard has been retained, as shown in the figure. The dimensions of the main building of the square-shaped structure are 60 m (length) × 45 m (width) × 8 m (height). Since the height of the decorative items and plants in the courtyard is less than 1.5 m, their impact on pedestrian height is negligible and can be ignored. The outdoor toilet is small, so its impact on wind speed is insignificant and can also be omitted. The models were converted to STL format for wind environment simulation, yielding wind environment simulation results at a height of 1.5 m above ground level for pedestrians [37].

2.3. Subjects of the Study

Qingdao is located in the southern part of the Shandong Peninsula, between 119°30′–121°00′ E longitude and 35°35′–37°09′ N latitude, surrounded by the sea on three sides and backed by mountains on one side (Figure 3). As a coastal hilly city, Qingdao features a terrain that is higher in the east and lower in the west, with undulations on both the northern and southern sides. Most of the traditional Liyuan in Qingdao are constructed in accordance with this terrain, generally parallel to the streets. Their external contours are determined by the direction of urban streets, typically square in shape, enclosed on all four sides, and forming a large courtyard in the center. These Liyuan are distributed in an orderly manner according to the terrain, exhibiting diversity in size, height, and form. This study selects Liyuan buildings of different types in the Dabaodao block, including single courtyards and courtyard clusters, as research objects to conduct CFD wind environment simulations.

This study utilizes long-term local meteorological data. Based on the wind rose diagram of Qingdao, it is concluded that, as a typical coastal mountainous city, Qingdao has a north temperate monsoon climate with a relatively high annual average wind speed of 4.6 m/s. The prevailing wind in winter is the northeast wind, with an average speed of 3.67 m/s and a maximum speed of 5.2 m/s; the prevailing wind in summer is the south wind, with an average speed of 5.2 m/s and a maximum speed of 6.0 m/s. For the simulation in this study, the summer prevailing south wind with a speed of 5.2 m/s is adopted (Figure 4).

2.4. Assessment Method

Wind comfort at the pedestrian level mainly focuses on the impact of wind force on the human body. To evaluate wind comfort in practical scenarios according to the Green Building Evaluation Standard (GB/T 50378-2019) [38], the division of wind comfort intervals has mainly been based on the mechanism of wind speed’s impact on human activities and thermal comfort perception over the past few decades [39]. Previous relevant studies have shown that when only discussing the summer wind environment of courtyards, Murakami, Morikawa, and Zhang Hua [40,41] divided wind speed into three characteristic intervals in their research: low wind zone (0–0.7 m/s), comfortable wind zone (0.7–2.9 m/s), and strong wind zone (>2.9 m/s). In the field of wind environment assessment for traditional dwellings, Wang Zefa et al. proposed a wind environment comfort evaluation standard corresponding to the physical meaning of modern wind speed, along with the cultural cognition of ancient wind speed [42].

The wind environment evaluation standard adopted in this study is the dual-dimensional wind environment evaluation system proposed by Professor Yang Junyan from Southeast University, which integrates modern physical parameters and human perceptual cognition, based on Professor Ng’s research on the thermal environment in Hong Kong (

Table 1. Wind comfort assessment standard.

Wind Speed (m/s)	Characteristic	Human Comfort Label	Physical Perception
V < 0.3	No wind	stagnant and oppressive	poor thermal comfort
0.3 ≤ V< 0.6	calm wind	barely perceptible or unnoticeable	relatively poor thermal comfort
0.6 ≤ V < 1.3	light wind	slightly comfortable	relatively low thermal comfort, tolerable
1.3 ≤ V < 5.0	gentle breeze	refreshed and comfortable	relatively good thermal comfort
5 ≤ V < 10	strong wind	a feeling of being blown away	satisfactory thermal comfort
10 ≤ V < 15	violent wind	too uncomfortable to move	uncomfortable thermal comfort

).

3. Results

3.1. Simulation Analysis of Natural Ventilation in Courtyard Buildings with Different Layouts of Sanitary Facilities

Against the backdrop of accelerating urbanization, it has been observed that the natural ventilation conditions of different sanitary facility layouts in courtyard buildings exhibit distinct characteristics. As shown in Figure 5, this study uses Junye Li and Yuxing Li as case studies to investigate how changes in toilet locations affect airflow and hygiene conditions in courtyard buildings. Taking Junyeli and Yuxingli as examples, based on the spatial positioning of toilets within the overall layout of the courtyard, two distinct forms of sanitary facility layout can be identified. The first involves toilets located on the opposite side of the courtyard entrance, while the second places toilets in the leeward area of the courtyard. Different toilet layout positions play distinct roles in airflow organization and spatial microclimate regulation, thereby exerting differentiated influences on the wind comfort of the courtyard.

Junyeli and Yuxingli are large courtyard clusters composed of multiple smaller inner courtyards. Taking the inner courtyards numbered ① to ⑥ in Junyeli as an example, the public toilets are located on the opposite side of the inner courtyard entrance, and this position is situated at the downwind end of the inner courtyard’s airflow circulation system. Under the combined influence of factors such as airflow diffusion, friction, and spatial morphology, the wind speed significantly decreases as the airflow follows the predetermined path to the end of the courtyard. This layout aligns with the airflow circulation patterns of the courtyard. Additionally, since the wind speed is lower at the location of the sanitary facilities, it helps reduce the likelihood of pollutants spreading extensively within the courtyard space through airflow circulation patterns. From a public health perspective, this effectively lowers the risk of disease transmission and has positive implications for creating a healthy living environment. Additionally, wind speed data in the figure shows that extremely low wind speeds are concentrated in the corners of spaces close to solid walls, while high-speed ventilation areas only appear near openings such as doors and vents. This indicates that the current design primarily relies on local strong winds to dilute the air and improve overall ventilation efficiency. Yuxingli consists of four connected inner courtyards, arranged from west to east as Courtyards ⑦ to ⑩, with public toilets located on the opposite side of the courtyard entrances. Further investigation revealed that, under the condition of equal courtyard lengths, there is a significant positive correlation between courtyard width and the area of low-wind-speed zones within the courtyard; that is, the wider the courtyard, the larger the area of low-wind-speed zones within it. This quantitative relationship provides a scientific basis for understanding the spatial morphology of courtyards and the characteristics of airflow distribution, offering important reference value for optimizing courtyard spatial layout and enhancing ventilation efficiency.

Additionally, simulations conducted using professional airflow modeling software revealed that the A–C courtyards in Junyeli have restrooms located in the leeward area. During the summer monsoon season, this area cleverly avoids direct exposure to the wind direction at the entrance, remaining within the low-wind-speed leeward zone. From the perspective of aerodynamic principles and pollutant dispersion mechanisms, this layout effectively reduces the risk of pollutant airflow directly passing through the toilet area from the entrance and subsequently infiltrating the courtyard living area. It prevents polluted air from recirculating, effectively preventing the deposition or suspension of viral aerosols, mold spores, and other contaminants on wall surfaces, and reduces the time these pollutants linger in courtyards. Through comparisons of multiple simulation datasets and actual case studies, this layout significantly reduces pollutant dispersion in the courtyard living area, playing a positive role in creating a healthier and more hygienic courtyard living environment and providing robust spatial layout support for improving residents’ quality of life.

3.2. Simulation Analysis of Wind Comfort in Different Functional Spaces of Courtyard Buildings

Given the significant differences in functional attributes among courtyard buildings, this study categorizes them into two main types based on their primary use: residential courtyard houses and commercial courtyard houses, both of which share comparable land area. This classification is significant because the two types exhibit markedly distinct characteristics in wind environment simulations.

Residential courtyards, as important spatial carriers for residents’ daily lives, are typically composed of a large number of small courtyards clustered together to meet the functional requirements of privacy and compactness. The public areas within each small courtyard are relatively cramped, and the narrow spaces between courtyards make it easy for airflow to be obstructed by surrounding building facades, resulting in complex local wind speed variations. As observed and analyzed in Figure 6b, due to the highly dense spatial layout of residential courtyards, wind speeds primarily range between 0 and 2.4 m/s. From the perspective of pedestrian activity, this low-wind-speed environment creates a relatively suitable atmosphere for daily pedestrian activities. However, due to the relatively weak wind force within each courtyard, low-speed vortex zones are easily formed in the corner areas of the courtyards, which are often represented by dark blue areas in wind environment simulation diagrams. The presence of such low-velocity vortex zones makes it difficult for pollutants such as exhaust gases generated within the courtyard to disperse and be transported outward, resulting in poor air quality within the courtyard, necessitating targeted optimization strategies.

From the perspective of overall architectural form and ventilation design, residential courtyard buildings typically only have doors on the street-facing facade, while the remaining three facades are closed off, lacking effective ventilation openings. This design pattern severely hinders airflow between the courtyard rooms and the courtyard, with wind speeds generally below 4.2 m/s. The limited number and improper placement of openings in the building envelope directly affect airflow paths and ventilation efficiency, as shown in the figure. Residential courtyard buildings typically have doors only on the street-facing facade, meaning that the intake and exhaust openings are on the same side. This can cause airflow to short-circuit, where fresh air is expelled immediately after entering, resulting in minimal airflow in areas far from the openings. The phenomenon of high-speed airflow concentrating around doorways also indicates that fresh air is expelled before it is fully mixed, reducing overall pollutant removal efficiency. Additionally, since door openings for ventilation are often at the same elevation, this weakens the thermal pressure effect. When all openings are at the same height, natural ventilation cannot rely on thermal or wind pressure, and hot air cannot rise and exit, leading to more significant accumulation of contaminated air. During the hot summer months, such ventilation conditions hinder the rapid dissipation of indoor heat, making it difficult to effectively lower indoor temperatures and exacerbating feelings of stuffiness. Additionally, poor air circulation severely impedes the adequate exchange of indoor and outdoor air. This also leads to a decline in indoor air quality. The longer the air remains stagnant, the poorer the ventilation effect, which may result in the accumulation of pollutants, increased CO₂ concentrations, and moisture buildup, significantly impacting indoor air quality and adversely affecting residents’ living comfort and health.

Courtyard buildings primarily used for commercial purposes typically feature a large courtyard surrounded by buildings, with a spacious and relatively open spatial layout that provides ample space for various commercial and social activities. Taking Guangxingli as a representative example, by the 1930s, Guangxingli had developed into a diverse and bustling area with a rich array of entertainment and cultural activities. The courtyard housed a variety of commercial establishments, including cinemas, photography studios, general stores, local product shops, dumpling shops, and children’s clothing stores. Given the high requirements for environmental comfort in commercial activities, compared to residential courtyards of similar size, commercial courtyards place greater emphasis on ventilation and air circulation in their layout design.

In terms of spatial layout, commercial courtyards typically feature multiple openings. As shown in Figure 6a, the entrances to courtyards primarily used for commercial purposes are cleverly positioned on the southern, northern, and eastern sides. This multi-directional entrance layout facilitates the entry and circulation of airflow. Wind environment test results indicate that wind speeds within courtyards primarily used for commercial purposes can consistently reach 3.6 m/s. Under such wind speed conditions, it is conducive to the formation of strong and sustained through-drafts within the courtyard. Leveraging its powerful airflow driving force, air pollutants within the courtyard are rapidly expelled, effectively preventing their accumulation, thereby significantly improving the air quality of the courtyard. This creates a healthy and comfortable air environment for commercial activities, holding significant importance for enhancing commercial operational efficiency and consumer experience.

3.3. Sensitivity Analysis of Wind Comfort Before and After the Renovation of Traditional Courtyard Buildings

3.3.1. Simulation Analysis Comparing the Wind Environment in the Courtyard Before and After the Renovation of a Single Building in a Courtyard

In the 1920s and 1930s, as the population in courtyard neighborhoods continued to grow, residents’ demand for usable space rose sharply. This practical need led to the gradual spread of illegal construction within courtyard areas. Such unauthorized construction activities have steadily eroded the originally open and public courtyard spaces, exerting a significant negative impact on the ventilation environment of courtyard areas. This has become a key factor constraining the improvement of wind environment quality in courtyard areas and their surrounding neighborhoods. This section examines the comparison of wind environment conditions in courtyards before and after the renovation of individual buildings in courtyard areas.

Taking Guangxingli as a typical case study, summer wind speed simulations using CFD software can visually analyze the comparison of ventilation conditions within single courtyards before and after renovation strategies. As shown in Simulation Figure 7a, before the courtyard was renovated, i.e., when illegal structures were present within the courtyard, the wind speed in most areas of the courtyard was generally below 1.2 m/s. When the wind speed is below 1.2 m/s, poor thermal comfort occurs because low wind speeds lead to poor air ventilation and outdoor thermal comfort issues. This results in a significant decline in pedestrian wind comfort perception, with the overall wind speed environment in Guangxingli deteriorating. As shown in Figure 7b, after the renovation of the courtyard buildings, the summer wind speeds in most areas of Guangxingli are consistently maintained between 0 and 3.0 m/s, and the wind speeds across the entire area are below 4.2 m/s, meeting human comfort standards. This significant change clearly demonstrates that reasonable spatial clearance and planning can effectively improve the microclimate environment of courtyards, creating a more comfortable and healthy outdoor living space for residents. This highlights the importance and necessity of the renovation strategy of demolishing illegal structures in optimizing courtyard wind environments and enhancing spatial quality.

Upon further investigation of the underlying mechanisms, the illegally constructed buildings within the courtyard severely disrupt the natural formation process of through-drafts in the courtyard. The disorderly, illegal structures have made the originally smooth ventilation pathways complex and convoluted, causing severe airflow obstruction and completely destroying the original good ventilation environment. This ventilation obstruction leads to deteriorated ventilation conditions during high-temperature periods in summer, resulting in a significant increase in internal temperatures within the courtyard. The oppressive heat accumulates within the courtyard space, making it difficult to dissipate the residual heat from summer, thereby greatly reducing residents’ living comfort. It should be noted that this study was conducted under simulated conditions with a single prevailing wind direction, which effectively reveals the core impact of the update strategy. However, the actual wind environment is subject to dynamic changes. At the same time, the simulation mainly focused on wind speed distribution and did not incorporate the comprehensive impact of real-time temperature changes during hot and humid periods in summer on thermal comfort, which may differ from the diversity found in reality.

3.3.2. Simulation Analysis Comparing Wind Conditions Before and After the Renovation of Clustered Courtyard Buildings

As shown in Figure 8a, for the clustered courtyard buildings (the building area within the black box in the figure), prior to renovation and upgrading, the majority of the accessible areas along the east and south streets of the clustered courtyard buildings experienced high wind speeds during the summer. In some sections of the east street, wind speeds exceeded the 5 m/s threshold for human comfort, while wind speeds along the east street ranged between 2.4 m/s and 6.0 m/s, creating stagnant wind conditions alternating with strong winds, resulting in an uncomfortable experience. As shown in Figure 8b, for the clustered courtyard buildings, after renovation and upgrading, wind speeds in the eastern street area of the square gradually decreased and stabilized within the range of 2.4 m/s to 4.2 m/s, falling within the comfortable wind speed range suitable for pedestrians to stand or rest for short periods. The open layout of the square facilitates rest and relaxation in this zone. The eastern edge of the square and the southern street area mostly have wind speeds within the comfortable range of 2.4 m/s to 4.2 m/s. Moving deeper into the newly opened square area, wind speeds decrease to the low wind speed range. Clearly, the wind environment quality of the clustered courtyard buildings improved after the renovation strategy was implemented, better aligning with human wind comfort requirements.

Analyzing the summer simulation results of the courtyard buildings before and after renovation, comparative studies reveal that the wind speed variability in the eastern street area of the renovated courtyard buildings is reduced compared to the pre-renovation courtyard buildings, resulting in greater stability. The primary reason for these results is that after renovation, the high-rise buildings in the southeast direction of the courtyard buildings were demolished, and the square area was expanded, leading to more stable overall wind speeds within the courtyard buildings. This indicates that the design of airflow linkage between the square and the main activity street can enhance street wind speed stability, narrow the range of wind speed fluctuations, and significantly extend the duration of pedestrian comfort. This suggests that in the renovation of historic districts, the strategy of incorporating open spaces and constructing streamlined ventilation corridors can effectively improve the overall wind environment of historic districts.

3.3.3. Simulation Analysis Comparing the Wind Environment of the Surrounding Neighborhoods Before and After the Renovation of the Courtyard Buildings

In an in-depth study of the before-and-after updates of courtyard building districts, the four adjacent plots of land formed by the streets surrounding the courtyard district, as shown in the figure, were selected as the research subjects. By using CFD software to simulate summer wind speeds, it is possible to visually analyze the simulated comparison of pedestrian wind conditions in the courtyard building district before and after the update strategy.

As shown in Figure 9a, the summer simulation results for the courtyard building district indicate that, prior to renovation, the majority of the wind speed ranges in the courtyard district’s active areas were approximately between 3.0 m/s and 4.2 m/s. The wind speeds around the triangular water supply building within the block remained at a relatively low level over the long term. As a result, the road space area exhibited a distinct low-wind zone characteristic, which was unfavorable for effective air circulation within the block. As shown in Figure 9b, the summer simulation results indicate that the removal of the triangular water supply building significantly improved the ventilation effect of the street. After demolition, wind speeds on the eastern side of the block increased significantly, with wind speeds in the newly created plaza area rising from 3.6 m/s to 4.8 m/s. Compared to the pre-renovation wind environment, this creates more favorable conditions for ventilation on the site. The demolition of the triangular water supply building creates an open space, restructuring the airflow pathways in this area. This effectively facilitated the smooth flow of air within the neighborhood. The series of wind environment changes triggered by the building demolition not only significantly optimized the neighborhood’s microclimate but also, from the perspective of human thermal comfort theory, the strong airflow can quickly dissipate a large amount of heat within the neighborhood, thereby effectively lowering the overall temperature. It has a positive effect in alleviating the impact of high temperatures in summer and significantly improves the comfort of pedestrians walking in the neighborhood during hot summer periods. This provides an important wind environment foundation for creating a comfortable and healthy outdoor space.

This study demonstrates that the strategy of optimizing ventilation by removing redundant structures significantly improves the efficiency of air circulation in the neighborhood, a crucial step toward enhancing the thermal comfort experience in outdoor spaces. The comfort of pedestrian wind environments requires an appropriate range of wind speeds, while also considering the combined effects of temperature, humidity, solar radiation, and other factors. Future research could further integrate field monitoring with thermal comfort models to conduct a comprehensive assessment of residents’ thermal perceptions across different seasons and time periods, thereby providing more precise guidance for the renovation design of courtyard neighborhoods and ultimately achieving the core objective of enhancing the quality of residents’ outdoor living.

4. Discussion

This study employs CFD simulation technology to systematically investigate the wind environment characteristics of the Qingdao Dabaodao District, focusing on analyzing and comparing the wind environment of courtyards with different layouts of sanitary facilities, different functional spaces, and different-scale spaces (individual courtyards, clustered courtyards, and surrounding courtyard districts) before and after renovation. The findings provide empirical evidence based on historical wisdom and climate responsiveness for healthy human habitation design. The research findings not only validate the intrinsic connection between traditional architectural forms and microclimate adaptability but also provide a scientific basis and practical pathways for optimizing healthy living environments in historical districts in the future.

The core arguments of this study resonate deeply with existing research in the field of courtyard microclimate. On the one hand, the research results confirm the mechanisms by which courtyard morphological parameters influence wind environments. Previous studies have demonstrated that elements such as courtyard plan shape, enclosure height, and opening locations directly impact ventilation efficiency by shaping airflow paths. This study further quantifies this relationship through CFD simulation: for example, in courtyards primarily used for commercial purposes, the large courtyard layout and multi-directional opening design (such as the three-sided entrances of Guangxingli) create efficient through-drafts, maintaining a stable wind speed of 3.6 m/s in summer, which aligns closely with previous findings that courtyard openness is positively correlated with ventilation efficiency. However, residential courtyards with dense small courtyards and closed facades (street-facing openings only) result in low-speed vortices (0–2.4 m/s), confirming previous observations that narrow, enclosed spaces hinder airflow circulation. On the other hand, this study found that the low-speed vortex zones in residential courtyards not only reduce human wind comfort but also exacerbate heat accumulation and pollutant retention, providing a new perspective for the synergistic optimization of thermal and wind environments. By comparing the wind environment differences between courtyards primarily used for commercial purposes (publicly open) and residential courtyards (privately enclosed), this study reveals the pathways through which functional requirements (sociocultural attributes) indirectly regulate microclimate via spatial form, expanding the dimensions of traditional architectural climate adaptability research.

In terms of historical district preservation, illegally constructed buildings (such as the unrenovated additions in Guangxingli) disrupt the original ventilation pathways, resulting in very low wind speeds. However, after removing the illegal structures, wind speeds return to a comfortable range. This suggests that historical district renovations must prioritize form preservation to avoid blindly damaging microclimate adaptability. In terms of healthy living environment construction, the study reveals the mechanism by which wind environments function as implicit health infrastructure. The layout of sanitary facilities in downwind areas can utilize low wind speed environments to reduce pollutant dispersion, which aligns with the requirements of the Green Building Evaluation Standard (GB/T 50378-2019) regarding the association between wind environments and public health safety. The stability of wind speeds improved after the renovation of cluster-style courtyard houses, meeting human comfort standards while reducing summer heat risks through enhanced ventilation. This provides further reference for assessing the health performance of historic districts under the Healthy China strategy. In terms of climate-responsive design, commercial courtyards maximize natural ventilation through large courtyards and multi-directional openings aligned with prevailing wind directions. This principle can be applied to modern urban design, for example, street canyons and building clusters should consider the guidance of dominant wind directions. The strategy of demolishing redundant buildings and creating squares in courtyard renovations provides an operational solution for optimizing wind environments in high-density cities through spatial restructuring. Looking ahead to future technological developments, to enhance the scientific management of densely populated historic urban areas, subsequent research could establish a CFD-GIS collaborative decision-making framework that integrates fluid dynamics simulation with spatial analysis techniques. This framework would support decision-making optimization for historic district conservation and renewal strategies, as well as improve the scientific rigor of decisions regarding sanitation facility layout and public health. GIS can serve as a spatial data hub, efficiently extracting and calculating building form parameters such as building density, wind-exposed area index, and sky view factor, to provide high-precision input for CFD simulations based on three-dimensional vector model analysis. This enables the construction of neighborhood-level ventilation potential assessments, identifying the minimum wind resistance paths between cold air sources and heat sink areas through morphological spatial pattern analysis, to guide the planning and design of urban ventilation corridors, thereby better assisting urban management and the creation of a favorable microclimate environment. Additionally, GIS-based accessibility analysis can be conducted to understand residents’ travel patterns, precisely identify high-demand densely populated areas, and clarify service demand gaps. By coupling with CFD pollutant dispersion models, PM2.5 concentration fields and wind environment exposure risk indices can be generated to establish negative screening rules for facility site selection, imposing environmental health constraints. Finally, by comprehensively considering factors such as demand, environment, and cost, a scientific hierarchical classification and optimized site selection for sanitation facility layout are generated. In summary, this study utilized CFD technology to reveal the intrinsic connection between courtyard building forms and wind comfort. Its value lies not only in providing a scientific basis for the renewal of the Dabaodao district but also in establishing an analytical framework linking historical forms, microclimate performance, and healthy living environments. This framework can serve as a methodological reference for the sustainable renewal of other traditional districts.

This study has the following limitations, which require further refinement in future research: First, the limitations of the simulation scenarios. This study focuses on the dominant south wind in summer and does not account for the influence of the northeast wind in winter or extreme weather such as typhoons. As Qingdao is located in a monsoon climate zone, seasonal differences in wind fields may lead to dynamic changes in the courtyard wind environment, necessitating further comparative simulations across multiple seasons and wind speed scenarios. Second, the simplification of influencing factors. The study primarily analyzed the effects of building layout and functional types but did not delve into the influence of factors such as vegetation configuration and thermal performance of building materials on wind-heat coupling effects. These factors may indirectly regulate wind environments by altering surface roughness or thermal radiation characteristics and should be incorporated into a multi-physics coupling analysis framework.

To address these limitations, future research can be advanced in the following areas: First, dynamic monitoring and optimization. Combining IoT technology to establish a long-term monitoring network for courtyard wind environments, real-time capture of spatio-temporal changes in wind speed, temperature, and pollutant concentrations, and providing data support for the dynamic optimization of simulation models. Second, future analyses will integrate the thermal comfort index with the combined effects of wind, heat, and humidity in a multi-physics field to assess the impact of microclimate quality on shaping healthy living environments. The following aspects can be explored in depth: (1) The mechanism by which solar radiation affects ventilation efficiency: Solar radiation energy is primarily converted into sensible heat flux, heating the near-surface air to form a thermal pressure gradient, which drives local circulation. (2) The coupled effects of humidity and pollutants: In high-humidity environments, aerosol growth due to moisture absorption alters deposition rates. Under high-humidity conditions, low wind speeds exacerbate PM2.5 retention, while increased wind speeds promote wet deposition and reduce particulate matter concentrations. Additionally, PM2.5 concentrations are closely associated with respiratory diseases, and increased concentrations significantly elevate the risk of respiratory disease infections in populations. (3) Humidity constraints on thermal comfort regulation: In environments with relatively high humidity, the minimum wind speed required to maintain thermal comfort standards is significantly higher than in dry environments. Third, adaptive translation of cultural genes: extracting the wisdom of multi-directional ventilation designs in courtyard buildings primarily used for commercial purposes, and developing design guidelines for wind corridors suitable for modern high-density cities, thereby achieving the contemporary inheritance of traditional architectural wisdom.

5. Conclusions

This study takes the Liyuan neighborhood in Dabaodao, Qingdao, as its research subject. Based on computational fluid dynamics (CFD) numerical simulation technology, it has systematically investigated the coupling relationship between the architectural spatial form elements of the Liyuan neighborhood and wind field characteristics, providing a scientific basis and practical pathways for optimizing the healthy living environment of historical neighborhoods. By conducting numerical simulations of the wind environment of different layouts of sanitary facilities, different functional spaces, and spaces of different scales (individual courtyard buildings, clustered courtyard buildings, and surrounding neighborhoods) before and after the renovation, the study found that factors such as building layout, street orientation, renovation strategy distribution, and building height significantly influence the wind environment of the Dabaodao Liyuan district, thereby affecting residents’ perceptions of wind comfort.

The main conclusions are as follows: First, the spatial layout of sanitary facilities has a significant impact on the wind environment and public health safety of courtyards. The study found that when toilets are located opposite the courtyard entrance or in the leeward area, the low wind speed environment can reduce the risk of pollutant dispersion with airflow, aligning with the spatial organization logic of healthy living environments. There is a positive correlation between the width of the inner courtyard and the area of the low wind speed zone, providing operational design references for future optimization of public facility layouts in courtyards.

Second, differentiated functional spatial forms create significant variations in wind environments. Residential courtyards, which prioritize privacy, feature dense small courtyard layouts that obstruct airflow and increase local vortex zones, resulting in wind speeds typically ranging from 0 to 2.4 m/s. While this meets basic activity requirements, it can lead to pollutant stagnation. Commercial courtyards, designed with open spaces and large courtyards with multiple openings to meet openness requirements, achieve wind speeds of up to 3.6 m/s, facilitating through-drafts and improving air circulation efficiency, thereby providing a more comfortable wind environment for public activities. To optimize the health and livability of residential environments, it is necessary to balance ventilation efficiency with spatial privacy. Specific strategies include appropriately increasing the openness between buildings, such as by creating ventilation corridors, and offsetting adjacent buildings horizontally in a front-to-back or left-to-right configuration. This allows airflow to bypass building edges and enter interior spaces, enhancing ventilation efficiency and improving thermal comfort. Increasing openings or windows on the windward side of building facades at a certain angle to the prevailing wind direction. Additionally, optimizing vegetation layout can be achieved by installing windbreak forests on the periphery, planting evergreen trees on the north side of courtyards to reduce winter cold air penetration, and arranging sparse woodlands and grasslands on the south side to guide summer winds into the space. Meanwhile, low shrubs can be used internally to block views and enhance privacy. By ensuring healthy ventilation requirements while effectively maintaining residential privacy, the design achieves synergistic optimization of wind environment and spatial quality.

Furthermore, renovation strategies at different spatial scales significantly optimize the wind environment of courtyard building districts. At the individual courtyard level, removing illegal structures eliminates ventilation obstacles, stabilizing summer wind speeds at 0–3.0 m/s, which meets human comfort standards. At the courtyard cluster level, creating plazas and constructing ventilation corridors can effectively reduce wind speed fluctuations, maintaining street wind speeds within the comfortable range of 2.4–4.2 m/s. At the neighborhood level, removing redundant buildings that obstruct airflow (such as triangular water supply structures) can reconfigure ventilation pathways, increase regional wind speeds, and enhance heat dissipation and pollutant dispersion capabilities. This provides a methodology for the sustainable renewal of historic districts that combines scientific rigor with cultural sensitivity. Future research could further validate simulation results using field monitoring data and expand to multi-physics coupling analysis involving thermal-humid environments and pollutant dispersion, while exploring the synergistic effects of various factors to provide more comprehensive decision support for precise renewal of traditional districts and the creation of healthy living environments.

In summary, through CFD wind environment simulation technology, this study analyzed various factors affecting wind comfort in Liyuan of the Dabaodao district and clarified the specific mechanisms of each factor. Additionally, future research can be expanded to multi-physical field coupling analysis, such as thermal–humid environments and pollutant dispersion, to provide more precise decision-making support for creating healthy living environments. This technical approach provides a methodological framework that combines scientific rigor with cultural sensitivity for the sustainable renewal of traditional neighborhoods. These research findings not only guide the planning, design, and renovation of the Dabaodao neighborhood, improving its wind environment quality and residents’ quality of life, but also lay the groundwork for future research. In the future, additional actual monitoring data can be integrated to validate and optimize simulation results, while further exploring the synergistic effects of different factors, thereby providing more precise support for the sustainable development of traditional neighborhoods.