Quantifying the impact of building layouts on wind–thermal environments: A computational fluid dynamics-based approach for optimizing plans and designs in high-temperature, low-wind regions

• Quantifies how interval, height, and layout impact wind-thermal dynamics in cities. • Shows small intervals in haphazard layouts boost wind speed and heat dissipation. • Identifies FAR limits to balance ventilation and reduce heat island effects. • Validates findings in Guangzhou, linking theory with real-world urban design. This study quantified the impact of building layouts on wind–thermal dynamics using computational fluid dynamics. Several neat and haphazard layouts were generated by varying the building interval, height, and length–width ratio. These scenarios were simulated using the Fluent software, and field verification was conducted in Changban village, Guangzhou. Statistical analysis of the wind–thermal characteristics revealed that 1) the building interval and height had significant orthogonal impacts on the wind and thermal dynamics. For intervals above 2 m, the wind speed decreased gradually with increasing height and stabilized at a height of 9 m. For building heights above 3 m, the wind speed decreased and then increased with increasing interval beyond the critical point of the canyon wind effect; 2) the length–width ratio and layout regularity had small but measurable impacts. For intervals exceeding 2 m, the neat layouts exhibited high wind speeds and lower temperatures. Conversely, for intervals below 2 m, the haphazard layouts induced high wind speeds and improved heat dissipation owing to the canyon effect. Similar trends were observed for length–width ratios of 2 and intervals above and below 4 m; 3) the four factors exhibited complex nonlinear relationships with the wind–thermal environment. The floor area ratio (FAR) was dominated by interval and height and showed a significant curvilinear relationship with the wind speed, which stabilized above FAR = 3. The temperature increased sharply above FAR = 1, which highlights the need to limit the FAR to mitigate urban heat island effects. These findings provide quantitative insights into the interplay between building layout and microclimate dynamics, offering practical guidance for building planning and design in low-latitude, high-temperature, and low-wind regions of the Northern Hemisphere.