Lattice Boltzmann method for open-channel flows

Abstract

Open-channel flows are very common and important flows occurring in both natural and artificial watercourses such as rivers, canals and drainages, and irrigation and navigation channels. Correct prediction and simulation of the flows play a crucial role in channel design, river management and flood control. In theory, the flows can be efficiently and accurately described by the shallow-water equations in most cases. In fact, the solution to these equations has turned out to be a very successful tool to model different free-surface flows such as tides, tsunami, dam breaks, dyke breaks, bores and broken waves. Although there are many numerical methods available for solving the shallow-water equations (e.g. the finite-element method), they are often complicated and computationally demanding. Over the last decade, the lattice Boltzmann method (LBM) has been developed as a very attractive numerical method in computational fluid dynamics. The method is extremely simple and efficient with its very easy treatment of boundary conditions and natural parallel processing, and is suitable for complex flows within complicated geometries. Consequently, the LBM has been developed for shallow-water equations with or without turbulence modelling (LABSWETM and LABSWE, respectively). This paper presents both methods and their application to typical open-channel flows. The results demonstrate the power, potential, applicability and accuracy of the LBM in simulations of many open-channel flows and also indicate that the method needs to be improved for some open-channel flow problems.