钟摆状态下湿颗粒坍塌流动行为及其动力相似性

Flow behaviors and dynamic similarity of wet granular collapse in the pendular state

基于建立的湿颗粒离散动力学模型,本文系统研究了钟摆状态下湿颗粒柱在重力驱动下的坍塌流动过程,主要考虑了颗粒粒径、液体表面张力系数和液体含量等参数对系统坍塌流动模式和动力学行为的影响。研究发现,在湿颗粒系统中,颗粒粒径和液体表面张力系数会改变颗粒间的毛细力大小,引起系统发生不同的坍塌流动模式,而液体含量仅定量影响颗粒坍塌后的堆积形态。在此基础上,进一步探讨了不同模式下系统坍塌流动行为与模型参数的相关性,发现无量纲Bond数是决定钟摆状态下湿颗粒物质坍塌流动动力学行为的本质因素。

The collapse of a wet granular column driven by gravity in the pendular state is systematically investigated using a discrete element model of wet particles,with effects of model parameters such as the particle size,liquid surface tension coefficient,and liquid content on the collapse regime and dynamics being primarily considered.It is discovered that particle size and liquid surface tension coefficient are both two relevant parameters in determining the collapse regimes by varying the capillary force between wet particles,whereas liquid content only has a quantitative effect on the final deposit morphology after collapse.On this basis,we have further discussed the dependence of flow behaviors on model parameters and find that the dimensionless Bond number is an essential factor in determining the collapse regimes of wet granular columns in the pendular state.