A wall-modeled large-eddy simulation database of an atmospheric flow over urban configurations (Teng et al . Phys. Fluids 37, 065129, 2025), obtained using a high-fidelity spectral-element method, is analyzed. The database comprises two urban geometries: (i) an in-line array of cubic prisms and (ii) a heterogeneous Michelstadt model, with plan area densities of λ p = 0 . 25 and 0.31, and frontal area densities of λ f = 0 . 25 and 0.24, respectively. In both cases, the incident wind angle is 0°. The corresponding Reynolds numbers based on the mean building heights are R e H = 5 . 0 × 1 0 6 and 6 . 0 × 1 0 6 , respectively ( H denotes the mean building height). The present study addresses the mean-flow behavior of the atmospheric boundary layer over these two urban configurations, with particular emphasis on the effects of urban configuration within the roughness sublayer. In addition to conventional mean statistics, turbulence anisotropy is characterized through the anisotropy invariant function and the Lumley triangle. The results reveal that heterogeneity in the Michelstadt configuration generates a more complex and spatially varying flow field, in contrast to the periodicity of the cube array. The thickness of the roughness sublayer in Michelstadt case is substantially higher than that in the array of cubic prisms. In both cases, the spatial distribution of the anisotropy invariant function exhibits an inverse relationship with the turbulent kinetic energy, attributed to the dominance of the streamwise Reynolds stress. These findings provide deeper insights into roughness-induced flow patterns and reference data for parameterizations within urban canopy. • Characterizes mean-flow regimes over two canonical urban configurations using high-fidelity wall-modeled large-eddy simulation. • Heterogeneous urban morphology produces more complex flow structures than periodic cube arrays, yielding a thicker roughness sublayer. • Streamwise Reynolds stress dominates turbulent kinetic energy above rooftops and within open spaces in both configurations. • Turbulence anisotropy exhibits an inverse relationship with turbulent kinetic energy.
Teng et al. (Fri,) studied this question.