Urban Interference Effects on the Aerodynamic Loads of a CAARC High-Rise Building: A Comparative RANS and DDES Study

Urban densification and high-rise buildings alter local wind flows, thereby affecting structural aerodynamic loads. To address this issue, the present numerical study investigates the insertion of a standard high-rise building within the Oklahoma City urban dataset. Computational Fluid Dynamics simulations were conducted across eight wind incidence angles (from 0° to 360° at 45° intervals) using two turbulence models, the steady-state Reynolds-averaged Navier–Stokes (RANS) approach with the k−ω shear stress transport (SST) model and the transient SST-based Delayed Detached-Eddy Simulation (SSTDDES) approach. Numerical validation against the Michelstadt experimental dataset showed satisfactory agreement for the mean urban-flow field. The aerodynamic analysis indicates that the surrounding neighborhood generally reduces several mean global loads through shielding, while producing strongly direction-dependent interference effects, particularly in the lateral and torsional responses. The SSTDDES simulations additionally exhibit substantial instantaneous load fluctuations that are not represented by the steady RANS formulation. Because experimental validation is restricted primarily to mean-flow quantities, these instantaneous extrema are interpreted comparatively rather than as experimentally validated design peak loads. The results demonstrate the importance of considering wind direction, surrounding morphology, and modeling assumptions when assessing aerodynamic loads on tall buildings in dense urban environments.