Yao Xiong-liang

The interaction between multiple bubbles and the free surface

The flow is assumed to be potential, and a boundary integral method is used to solve the Laplace equation for the velocity potential to investigate the shape and the position of the bubble. A 3D code to study the bubble dynamics is developed, and the calculation results agree well with the experimental data. Numerical analyses are carried out for the interaction between multiple bubbles near the free surface including in-phase and out-of-phase bubbles. The calculation result shows that the bubble period increases with the decrease of the distance between bubble centres because of the depression effect between multiple bubbles. The depression has no relationship with the free surface and it is more apparent for out-of-phase bubbles. There are great differences in dynamic behaviour between the in-phase bubbles and the out-of-phase bubbles due to the depression effect. Furthermore, the interaction among eight bubbles is simulated with a three-dimensional model, and the evolving process and the relevant physical phenomena are presented. These phenomena can give a reference to the future work on the power of bubbles induced by multiple charges exploding simultaneously or continuously.

A numerical investigation of bubble dynamics based on the potential-flow theory

In this paper, the flow field is assumed to be inviscid, irrotational and incompressible, triangular elements are adopted to discretize the boundary of flow field, the boundary integral method is used to solve the flow field and the Mixed-Eulerian-Lagrangian method is applied to simulate the evolution of bubble. Three-dimensional smoothing method is used to smooth the bubble surface and the velocity potential to make the computing process more accurate and stable. In the analysis process, three-dimensional model simulates the dynamics of a bubble in the free field, gravitational field and near the rigid wall respectively, and the calculated results coincide well with the exact results and experimental data, which show that the algorithm and 3D model in this paper are of high accuracy. Calculation process indicates that bubble takes on strong non-linear under the combine effect of gravity and rigid wall.

Research on global optimization method for shock-resistance of ship systems

Considering the complexity of ship systems, the global optimum design problem on anti-shock resistance of ship systems is analyzed in this paper. The investment on anti-shock resistance of ship systems is taken as optimum objective function, and anti-shock strength of equipments in system is taken as optimum variable. Then the relationship between investment and anti-shock ability of equipments and systems was preliminarily discussed in this paper. Based on the optimum design method between anti-shock investment and performance, three mathematic models of global optimization were built according to practical engineering situation. Furthermore, the numerical analysis method was summarized. At last, the shock-resistance of some a power system was optimized by the method presented in this paper.