摘要
目前,以模拟推移质冲淤为主要对象的河工模型试验,其比尺设计均按平床起动流速和输沙率相似加以考虑.实际上天然河流纵向起伏不平,山区性河流更呈深潭与浅滩交替出现的现象,而当模型又采取几何变态时,坡面上泥沙的起动和输移率的相似就会产生一定程度的偏离.本文通过对变态模型有关相似比尺的分析,说明了几何变态所导致的顺水流方向正、负坡面上和岸坡坡面上泥沙起动和输沙率相似性偏离的性质、偏离的程度及其影响因素,为在模型设计中合理地选定几何变态率和模型沙提供依据.
Scale distortion model is commonly used to simulate the fluvial process of a natural river. On the study of the fluvial process caused by gravel bed load motion, the model scales of the incipient velocity and the rate of bed load transport are usually designed on the condition of a flat river bed. Actually, the longitudinal profile of river bed is generally uneven, but rises and falls along the flow direction with a certain slope, especially for the mountainous rivers. In such case, scale distortion will result in dissimilarities both on incipient motion and the rate of bed load transport on these river reaches. Based on the analysis of the similarity laws of gravel bed load motion on a gradient bed, the characteristics and the extents of the deviations of similarity caused by scale distortion are revealed in detail in this paper. Therefore, the rate of the scale distortion should be carefully designed and the model sand should also be properly selected in a physical model study.
出处
《泥沙研究》
CSCD
北大核心
1992年第1期9-20,共12页
Journal of Sediment Research
