The gas-solids flow in a bubbling bed was simulated by the combination approach of computational fluid dynamics (CFD) and discrete element method (DEM)

and the simulation results were used to investigate the microscopic characteristics of bubbles and particles. The particle fluctuating energy spectrum was calculated to find out the flow field intermittency in the bubbling bed. Different features of flow field intermittency were found at different locations of bubbling bed by comparing the flatness factor of fluctuation velocity of particles. With increasing bed height

flow field intermittency was weakened. Along the radial direction

the flow field intermittency in the transition region was stronger than that in the wall and center region. Continuous wavelet transform was used to investigate the coherent structure of particles and its evolution process

as well as the relation between coherent structure of particles and flow behavior of bubbles and particles on different scales.