Lattice Boltzmann model and its GPU acceleration for transient flow in channel and pressurized pipe combined water delivery system

Abstract The open channel and pressurized pipe combined water delivery systems usually have long pipelines, many overflow structures, and especially with two different flow regimes, making the transient simulations complicated and time-consuming. A graphics processing unit (GPU)-accelerated lattice Boltzmann model (LBM) is proposed to solve the above problem. The LBM model for water hammer in pipes is improved by introducing the one dimensional with two lattice velocities discrete model (D1Q2). Compared with the existing the one dimensional with three lattice velocities discrete model, the D1Q2 model has reduced the occupation of computational resources, and the boundary processing has become simple. By simulating the transient process of a pipe network system, the results are in good agreement with those of the method of characteristics (MOC), and the speedup ratio reaches 60.5. Then, the water hammer LBM model and shallow water LBM model are coupled to simulate the transient process of the open channel and pressurized pipe combined water delivery system, and its GPU parallel computing scheme is achieved. Practical application shows that the results agree well with those of MOC, and the maximum speedup ratio reaches 92.96, indicating the great application potential of the proposed model.