基于应力波动的修正非局部流变模型

A MODIFIED NONLOCAL RHEOLOGY MODEL FOR DENSE GRANULAR FLOW

基于Pouliquen提出的非局部流变模型,考虑颗粒流中某个位置重新排列引起的自激发过程,详细分析颗粒介质中应力波动幅值的概率密度分布形式以及剪切速率与体积分数的耦合作用,提出一种修正的非局部流变模型.采用此修正非局部流变模型对斜面剪切颗粒流的流动特性进行了预测,颗粒流动的临界厚度、平均流动速度及剪切速率廓线的预测结果与实验结果定量吻合.此修正模型的提出为复杂的密集颗粒流的描述和表征提供了一种新的研究思路.

In dense granular flows, a non-local rheology theory was proposed by Pouliquen et al. based on the idea of a self-activated process, in which a rearrangement at one position will be trigged by stress fluctuation due to rearrangements elsewhere in the material. Taking into account the probability density distribution of stress fluctuation amplitude in granular materials and the coupling effect between shear rate and volume fraction in iterative calculation, a modified non-local rheological model was proposed in order to describe the dense granular flow more accurately. Due that dense granular flows down inclines preserve this complexity but remain simple enough for detailed analysis, this modified model was applied to predict the rheological characteristics of flows down a rough inclined plane. Compared to the previous non-local rheological model, the predicted results based on the present modified model, including the critical thickness,depth-averaged velocity and shear rate profile, are quantitatively better consistent with the existing experimental and simulating results.