冲刷物理模型试验的比尺效应研究

Study of scale effect in scour physical-model experiments

冲刷物理模型试验的比尺效应主要是由模型沙不满足泥沙运动相似的要求所产生。因此在将试验结果外推到原型时会产生较大偏差。全面分析了系列模型实验法、经验公式法和相似模型试验法减少或者消除比尺效应的优缺点;提出了经验公式用于分析试验结果的偏差程度。认为满足泥沙起动相似和动床阻力相似是冲刷物理模型设计和模型沙选用的重要原则。

The scale effect in scour physical-model experiments is mainly caused by dissatisfaction of mobility similarity of model sediment. It leads deviations when the experimental result is extrapolated to the prototype. Advantages and disadvantages of different approaches including series scale-model test, prediction equation- targeted flume test and similitude model test to alleviate scale effects are discussed; an empirical formula is suggested to assess the deviation of test results. The most important principle in designing a scour physical- model test including the choice of model sediment is to meet the requirement of incipient motion similarity of bed particle as well as movable-bed resistance similarity.