沙波与刚性非淹没植物复合床面曼宁系数特征研究

Study on Manning s Value Characteristics of Compound Bed Form Combined of Unsubmerged Rigid Vegetation and Sand Dunes

通过室内水槽试验研究单一沙波床面、单一刚性非淹没植物床面以及沙波与刚性非淹没植物复合床面3种工况下曼宁系数与相对流速的关系。试验表明,单一沙波床面、单一刚性非淹没植物床面工况水流的曼宁系数随着相对流速的增大而增大;沙波与植物复合床面工况受沙波和植物共同的作用,由于水流结构发生变化,水流的曼宁系数随着相对流速的增大呈现先减小后增大的规律;复合床面的曼宁系数不能通过单一沙波床面和单一植物床面工况水流的曼宁系数叠加得到。

In this study,laboratory experiments are used to study the Manning s value and relative velocity value under conditions of single sand dune bed form,single unsubmerged rigid vegetated bed form and compound bed form combined of unsubmerged rigid vegetation and sand dunes.The results show that the Manning s value increases with the increase of relative velocity under the condition of single sand wave bed form and single rigid unsubmerged vegetated bed form;under the condition of compound bed form combined of unsubmerged rigid vegetation and sand dunes,the Manning s value decreases first and then increases with the increase of relative velocity due to the change of flow structure.The comprehensive Manning s value in compound bed form cannot be obtained through simple superposition of Manning s value of single vegetated and single sand dune bed form.