A multicell one-dimensional stochastic wall model for Large-Eddy Simulation: validation and application

Abstract In this study, a multicell extension of the one-dimensional turbulence (ODT) stochastic wall model for Large-Eddy Simulation is introduced and validated. The proposed formulation improves the representation of the near-surface flow by replacing multiple wall-adjacent LES cells in the vertical direction with an extended ODT domain, without requiring additional refinement of the LES grid. The performance of the multicell-LES-ODT coupling is assessed through a series of numerical tests, including rough and smooth channel flows, as well as atmospheric boundary layer (ABL) simulations under neutral, stable, and unstable stratification. The results show that the proposed approach preserves the overall behavior of the main turbulence statistics, while deviations increase with the extent of the ODT region due to the modeling error introduced in the LES solution. The applicability of the method to realistic environmental flows is further demonstrated through a simulation of the neutral ABL with the Amazon rainforest. The multicell-LES-ODT approach captures the main features of canopy-induced turbulence as well as the overall structure of the atmospheric boundary layer. These results indicate that the proposed coupling provides a robust and flexible alternative to traditional wall models for wall-bounded flows that require enhanced resolution in the near-wall region.