Numerical Study of Inclined Wall and Pressure Estimation under Free-Surface Flow using Lattice Boltzmann Method
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As a modern method in computational fluid dynamics, the lattice Boltzmann method has great popularity among researchers. Its primary use is the simulation of incompressible flows. It has computational advantages over conventional methods such as the finite element method, and the finite volume method. However, the implementation of boundary conditions is still an unsolved topic for this method. The method is defined on a Cartesian grid such that complex geometries need special treatment as they are generally not aligned with the grid lines. In the present study, inclined wall-obstacle treatment is investigated with two most efficient boundary conditions, named Bouzidi's method and Yu's method, in a dam breaking application. Assuming that the inclined wall treatment is a first step of complex geometry implementation, generalized algorithm of inclined wall is presented initially. Different slope of angles are tested for both boundary conditions. Through this algorithm and presented results, we showed our study is valid for different angles. In the case of a trapezoidal obstacle placed around the middle part of computational domain, we have validated our study with the experiment data. The results of the two boundary conditions are presented. Although the graphs showing the height of free surface in different positions are not exactly overlapped, the general pattern and maximum heights of free surface are well predicted. In addition, there is no significant difference observed between Bouzidi's and Yu's method. The impact pressure values acting on the right vertical wall of the computational domain are presented. For 3 different points chosen at the wall, pressure results have been obtained from Bouzidi's, Yu's, and halfway boundary conditions.