Numerical Simulation And Preliminary Experimental Study On Behaviors Of Spherical Shell In Granular Shear Flow

Many particle flow phenomenon,such as debris flow,avalanche and landslide,are widespread in nature and adversely affect human life and production.Particle flow,which belongs to non-classical medium flow,have not been explained properly for its behaviors of overall liquidity.Effective characterization parameters and related research for describing particle flow need to be further studied.Spherical shell motion by the action of particle shear flow is taken for research objects in this paper.With the object-oriented C++ programming approach,a DEM numerical model which using the algorithm of three-dimensional periodic boundary has been established based on CUDA parallel supercomputing technique.Motion behaviors of spherical shell in particle shear flow has been discussed in detail.In this paper,corresponding experimental design and primary experiments of particle shear flow also have been developed.The main works of this paper are:1.With the object-oriented C++ programming approach,CUDA is applied to build DEM computation model.The algorithm of three-dimensional periodic boundary has been presented and used into numerical simulation of spherical shell motion in particle shear flow.The results show that the algorithm of three-dimensional periodic boundary based on CUDA is feasible and substantial to enhance computational efficiency.2.A strip of three-dimensional periodic boundary and an annular boundary have been adopted to study spherical shell behaviors in horizontal and annular particle shear flow respectively.The results show that spherical shell always rise up in horizontal shear flow.The height of slope is proportional to rising height of shell while particle diameter and shell depth are inversely proportional to rising height of shell.In annular shear flow,different shell movement states of rising or falling appear due to diverse rotating speed,particle diameter and shell depth.3.Spherical shell experiments with particle shear flow has been designed and constructed based on computation model and parameters setting in numerical simulation.Phenomenon of spherical shell floating on surface of particle medium has been observed in annular shear flow and specific research of shell behaviors has been finished with different rotating speeds.Findings indicate that spherical shell always floats on particle surface in shear flow after a period of time and rotating speed is inversely proportional to floating time of shell.