Temperature wall function boundary condition in lattice Boltzmann method for indoor thermal turbulent flow

This work introduces a straightforward thermal wall boundary framework for the lattice Boltzmann method, incorporating a wall function model for temperature. Accurate heat flux transfer near the boundary is achieved by evaluating the non-dimensional distance of near-wall grid points and dynamically modifying the wall temperature. The proposed boundary condition was validated through large- eddy simulation based on LBM (LBM-LES) applied to an indoor natural convection turbulent flow. Results demonstrate that the new wall treatment markedly improves the prediction accuracy of both mean and fluctuating temperatures, especially under coarse grid conditions. This approach shows strong potential for LBM-LES applications in building thermal fluid simulations by enhancing temperature accuracy— particularly near walls—while reducing grid dependency.