摘要
颗粒流的应力由三部分:弥散应力、摩擦应力和碰撞应力组成。对快速颗粒流来说,颗粒碰撞应力占优势,其他应力可略去不计。颗粒流模型非常适合描述颗粒间流体相互作用较小的无粘泥石流或水石流,作为应用例子的是:从颗粒流模型导出的速度分布与无粘泥石流的大量试验测量结果相一致。除颗粒流模型外,在泥石流研究中应用较多的还有宾汉体模型、膨胀体模型和粘塑体模型。它们都能作为特例,包括在两相流模型之中。
Great achievements in recent studies of granular flows make it possible to develop a new debris flow model ,i. e. ,the granular flow model for debris flow. The granular flow with a prominent Collisional action among particles is a Special solid-liquid (or gas)two-phase flow,in which the total stress is composed of the dispersive stress,frictional stress and collisional stress. When the particle concentration is high the dispersive stress may be neglected ,and thus the collisional stress becomes the principal one for the rapid granular flow. The granular flow model is suitable for the cohesionless debris flow or .the water-rock flow, in Which the little effect of liquid fluid exists.Besides the new developed granular flow model, the Bingham fluid model, dilatant fluid model and viscoplastic fluid model are usually used to describe debris flows. In fact, each of the mentioned model is applicable only to a certain type of debris flow and thus should be considered as a special case of a two-phase flow model. In other words,the two-phase flow model is more reasonable than others since both collisional actions among particles and the liquid fluid effects on particles are considered simultaneously. Because of its complexity, the two-phase flow model is more difficult to be used to solve the actual problems of debris flow in the ordinary case. Therefore, the separate models mentioned above nave still found wide applications for its simplicity,especially for the granular flow model which is constructed on a refined theory. From the granular flow model,the mechanism of cohesionless debris flow is investigated. Agreement between the measured and theoretical results such as the vertical velocity distribution shows that the present model is reasonable.
出处
《山地研究》
CSCD
1992年第1期1-10,共10页
基金
中国科学院东川泥石流观测研究站基金
关键词
泥石流
颗粒流
模型
debris flow, granular flow, model
