Wall-Modeled Unstructured Single-Step and Simplified Lattice Boltzmann Method for Turbulent Flows in Curved Boundaries
This work presents an efficient unstructured CFD solver based on the Single-Step and Simplified Lattice Boltzmann Method (SSLBM), extended with a wall model to create a wall-modeled USSLBM framework (WM-USSLBM). The solver enables simulations of turbulent flows around curved geometries by combining the SSLBM formulation with a fully spatial interpolation stage, thereby overcoming the geometric limitations of structured Cartesian grids and supporting hybrid structured–unstructured domains. The proposed solver includes all current SSLBM capabilities, including the coupling of the Vreman Large Eddy Simulation (LES) turbulence model with a Werner–Wengle wall model, allowing high-Reynolds-number simulations with near-wall resolutions ranging from y+ ≈ 1 (baseline USSLBM) to wall-modeled spacings of y+ ≈ 50. The solver is designed for Graphics Processing Unit (GPU) acceleration to maximize performance. In this paper, the baseline USSLBM solver is evaluated using a high-Reynolds-number benchmark case of the NACA4412 airfoil at several angles of attack. A qualitative macroscopic velocity field is presented, followed by a quantitative comparison of the pressure coefficient and aerodynamic forces with numerical and experimental data reported in the literature. The results demonstrate good agreement and highlight the versatility and potential of both the USSLBM and WM-USSLBM solvers for complex turbulent flow simulations.
