Numerical study on shock-dusty gas cylinder interaction

摘要

The interaction of a planar shock wave with a dusty-gas cylinder is numerically studied by a compressible multi-component solver with an adaptive mesh refinement technique.The influence of non-equilibrium effect caused by the particle relaxation,which is closely related to the particle radius and shock strength,on the evolution of particle cylinder is emphasized.For a very small particle radius,the particle cloud behaves like an equilibrium gas cylinder with the same physical properties as those of the gas-particle mixture.Specifically,the transmitted shock converges continually within the cylinder and then focuses at a region near the downstream interface,producing a local high-pressure zone followed by a particle jet.Also,noticeable secondary instabilities emerge along the cylinder edge and the evident particle roll-up causes relatively large width and height of the shocked cylinder.As the particle radius increases,the flow features approach those of a frozen flow of pure air,e.g.,the transmitted shock propagates more quickly with a weaker strength and a smaller curvature,resulting in an increasingly weakened shock focusing and particle jet.Also,particles would escape from the vortex core formed at late stages due to the larger inertia,inducing a greater particle dispersion.It is found that a large particle radius as well as a strong incident shock can facilitate such particle escape.The theory ofLuo et al.(J.Fluid Mech.,2007) combined with the Samtaney-Zabusky (SZ) circulation model (J.Fluid Mech.,1994) can reasonably explain the high dependence of particle escape on the particle radius and shock strength.