A three-dimensional simulation on deformation and instability of low-density spherical bubble induced by incident and reflected shock waves is performed with Navier-Stokes equations.A computational model validated by experiments is used to study deformation of bubbles,formation and three-dimensional instability of vortex rings.It is found that low.density spherical bubbles can deform and form vortex rings with different rotating directions along streamwise direction induced by incident and reflected shock waves. Baroclinic effect is the main reason for formation of vortex rings.Vortex rings move due to self-induced effect and flow field velocity. And azimuthal instability OCCURS due to disturbance.Finally.vortex rings may induce turbulent flow a8 they form a complicated structure dominated by small-scale streamwise vortices.

A variable-density stochastic vortex model is used in simulating H₂/O₂/N₂ turbulent jet diffusion flames,in which turbulence is modeled by vortex sample,vortex suppression and vortex turnover.A large-vortex suppression mechanism for variable density reacting flows is presented and effects of parameters in model prediction are discussed in detail.It shows that the modified model can predict reasonably H₂/O₂/N₂ jet flame structures,and reflect characteristics of turbulent vortices.It also reveals that various parameters in vortex sample and vortex suppression affect results of the model.

A dynamical storage/deletion algorithm for acceleration of chemical reaction calculation is proposed which deals with stiff chemical source term in reactive flows.The algorithm is applied to two-dimensional gaseous detonation.Two deletion approaches, global deletion and node deletion,are developed and compared with traditional direct integration(DI) algorithm.It shows that the proposed algorithm ensures computational accuracy and relaxes stringent limitation on computer memory.With fixed size of data table,computational speedup factor increases with increament of tolerance error.With same tolerance error,speedup factor of node deletion approach is higher than that of global deletion.The algorithm shows advantages in solving transient reactive flows.

Taking aluminum dust as an example, the generation and acceleration of shock wave induced by weak Ignition in dust suspension in a long horizontal combustion tube have been studied theoretically and numerically. Two fluid model and TVD technique are used to calculate the flow field of gas phase and particle phase and Arrihenius law and k-ε model considering the near wall turbulent are used to calculate the chemical reaction. The wall turbulent plays a important role in the flame acceleration and combustion induce shock process. Simulated results reveal the innate character from compressive wave to shock wave in combustible dust suspension and the flow field parameter distribution. The simulated and measured results are compared with a good agreement.

Numerial methods,including Lagrangian's transformation, physical splitting and self-adaptive grid technique, are used for enlarging domain of calculation and simulating the whole process of aluminium dust explosion in 20 litre closed spherical chamber in this paper. The results from simulation are in good agreement with measured experiment results.