Lattice Boltzmann method for flow through vegetation

Abstract

Recently wildland/forest fires have dramatic impact on the environment and society. Therefore, it is vital to understand wildland/forest fires spread dynamics to prevent its hazardous effects on society and environment. Models based on Computational Fluid Dynamics (CFD) have been developed and improved to investigate the dynamics of the wildland/forest fires. Even for CFD based physical models, a robust understanding of the processes (i.e. drag, convective heat transfer and radiation) driving fire spread is missing for small scale. The present study focuses on obtaining drag coefficient for the complex vegetation structures in small scales by using Lattice Boltzmann method (LBM). Ultimately, the drag coefficient can be used in detailed wildland/forest fire spread models to analyze the physical mechanisms driving the fire spread in vegetation. The Lattice Boltzmann (LBM) is a relatively new numerical approach for solving Navier-Stokes equations. LBM has advantages such as simplicity, efficiency, easy treatment of boundary conditions, easy parallelization in simulating fluid flow and heat transfer. The developed model is validated with experiment for a cylinder in cross flow in the literature. The results show that LBM method can be used for the flow in complex distribution of vegetation.