关键词: 格子Boltzmann方法, 渗流场, 2D扫描切片, 数值模拟

Abstract: Mesoscopic seepage field of real soil is simulated based on lattice Boltzmann method. In this simulation, the basic model D2Q9 is used; and the inlet and outlet boundaries are constructed by setting the non-equilibrium extrapolation format. The soil particles boundary as well as left and right waterproof boundaries are set by the bounce-back format. At first, the data denoted by physical units from experiments are transformed into lattice units. According to data structure generated by CT scanned slices, the corresponding calculation program is applied to simulate mesoscopic seepage field of real soil. Finally, the results of lattice units are transform into physical units once again. The variation of seepage velocity is analyzed; and the whole and partial distributions of seepage field are obtained. The results show that: 1) Seepage velocity U finally reaches a relatively stable figure in pore channels over time. Accurate time T is obtained from the beginning of seepage to the steady-state of seepage. 2) The average seepage velocity gradually decreases along with the negative direction of y axis from the inlet boundary; and it is less than the average seepage velocity in inlet boundary. 3) The quantity of seepage is dominated by the connectivity and pore size of channels. The maximum seepage velocity is concentrated in a narrow channel. The velocity in closed pore channel and pore is zero. Lattice Boltzmann method is effective in simulating two dimensional CT scanned slice and can be used to research the mechanism of real seepage field quantitatively and accurately.

Key words: lattice Boltzmann method, seepage field, 2D scanned slice, numerical simulation