High velocity flow simulation using lattice Boltzmann method with no-free-parameter dissipation scheme

A finite difference lattice Boltzmann method of second-order accuracy in time is developed based on non-oscillatory scheme with no-free-parameter dissipation (NND) difference scheme in this paper. The NND lattice Boltzmann method is used to simulate high-speed flows by constructing a new equilibrium distribution function of the lattice Boltzmann method.Compared with a variation of lattice Boltzmann method developed by Qu, et al., the present method can capture shock waves and handle oscillations of high velocity flows accurately in larger time steps and in shorter computing time. Numerical results indicate the correctness and capability of simulating shock wave interactions of the NND lattice Boltzmann method.     

Simulation of two-phase flows of a droplet impacting on a liquid film with an improved lattice Boltzmann model

Based on the lattice Boltzmann method (LBM), an improved pseudo-potential model, combined with a method of adding force term, is used to simulate the two-phase flows caused by a liquid droplet impacting on a liquid film. In this model, the different phases are treated as one fluid, and the interfaces between the vapor and liquid phases can be obtained by density value of the fluid. This variant of the LBM allows one to obtain the densities of vapor and liquid with high accuracy. The model is validated by an example of phase separation. The early stage of the impact of droplet on liquid film is simulated, and the results are qualitatively consistent with physical phenomena.     

Study on One—Dimensional Model of Traffic Flow with Stochastic Deceleration via Lattice Boltzmann Method

One-dimensional traffic model was studied with the consideration of stochastic deceleration by using the lattice Boltzmannmethod.The evolution equation for vehicle density was derived,which has the form of the Burgers equation exhibiting the effect of viscosity corresponding to the deceleration.The simulation with the model shows that the variation of vehicle density in space tends to a periodic one,which implies the existence of kinematic waves in the 1D traffic flow and coincides with theoretical prediction.     

Parallel communication optimization based on least square method for LBM

Efficient communication is important to every parallel algorithm. A parallel communication optimization is introduced into lattice Boltzmann method (LBM). It relies on a simplified communication strategy which is implemented by least square method. After testing the improved algorithm on parallel platform, the experimental results show that compared with normal parallel lattice Boltzmann algorithm, it provides better stability, higher performance while maintaining the same accuracy.