Simulation of 2D sudden-expansion flow using the LB method.

The d2q9 model with the new interpolation method on nonunifrom gird, based on Lattice-Boltzmann (LB) equation, is used to simulate a 2D sudden-expansion flow. The results of LB simulation suggest, compared with other models, such as LES model, that precision of LB method is the same as LES model. On the other hand, it gains time and the code of calculation is simple. Although 2D sudden-expansion flow is very complex, the Lattice-Boltzmann method can get good performance. LB method will be also applicable to flow and sediment transport in natural rivers.