黄河下游床面形态判别方法探讨

Research on discrimination of bed forms in the lower reach of Yellow River

基于床面形态控制数理论,结合已有水槽试验研究成果,分析了床面形态控制数与不同床面形态的对应关系,提出了包括沙粒弗劳德数及相对水深(水深与泥沙中值粒径之比,下同)的床面形态参数,论述了简化床面形态控制数的计算方法及适用范围,研究了床面形态控制数与床面形态参数之间的相互关系及适用性;结合黄河下游床面形态运动特征,建立了床面形态判别方法。研究认为床面形态控制数能够反映高、低能态区的水流阻力特征;床面形态控制数与床面形态参数之间的关系,既适用于室内水槽试验也适用于天然河流;建立的黄河下游床面形态判别方法,得到了野外实测资料的初步检验,能够用于黄河下游不同能态区床面形态的判别。

Based on the bed form control factor theory and the existing flume experimental data,the correspondence between values taken by the control factor and different bed form configurations is analyzed.A bed form parameters including the particle Froude number and the relative depth（ratio of depth to median diameter of sediment particle） are proposed.In addition,a computational method on the basis of simplified control factor m,and its scope of application are introduced.The adaptability of the relationship between bed form control factor and the bed form parameter is discussed.With the relationship and the characteristics of bed form movement observed in the lower reach of Yellow River,a method to discriminate bed forms is established.The study suggests that the flow resistance characteristics in upper and lower flow regimes can be described by the control factor m,and the relationship between the control factor m and the bed form parameter exists not only in the laboratory flume experiments but also in the natural river systems.The preliminarily test of the established method to discriminate various bed form phases is done using the field observations.The result shows that the method is able to discriminate bed forms in different flow regimes in the lower reach of Yellow River.