CFD Investigation of Wind-Structure Interactions in Dense Urban Environment: Effects of Spacing Between Buildings

Dense urban developments with closely spaced high-rise buildings create complex wind–structure interactions that are not fully captured by existing studies, which often focus on isolated buildings or lack rigorous mesh optimisation and validation; this study addresses that gap by systematically examining how inter-building spacing modifies wind-induced pressures and velocity fields. The aim is to establish a validated, computationally efficient CFD framework for multi-building interference, with specific objectives to: (i) quantify the effects of spacing on windward pressures and suction zones under both uniform and atmospheric boundary layer inflows, and (ii) optimise a mesh and turbulence-modelling strategy that is suitable for routine engineering design workflows. The present study uses validated Reynolds-Averaged Navier–Stokes (RANS) simulations with a standard k–epsilon model under both uniform and atmospheric boundary layer inflows. A mesh sensitivity analysis identifies an optimal grid of 1.7 million cells and validation against CAARC wind tunnel data shows close agreement in ABL profiles and peak pressure coefficients on windward faces. Despite its simplicity, the standard k–epsilon closure is adopted as a practical engineering choice because, for tall-building cases, it reproduces time-averaged pressures and moments comparable to more advanced models but at far lower computational cost, enabling parametric studies across multiple spacing configurations. Reducing spacing from 250 m to 50 m increases peak windward pressures on the downstream taller building by approximately 8% near the top and amplifies minimum suction near the base by up to 60%, with local pressure magnitudes reaching 0.50 kPa and producing up to 20%..(read more in PDF file)