Bed Form Resistances in Open Channel Flows
Bed Form Resistances in Open Channel Flows
复制标题
明渠水流中的床形阻力
DOI：
10.1061/(asce)0733-9429(1990)116:6(799
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发表时间：
1990
影响因子：
2.4
通讯作者：
C. Mendoza
中科院分区：
文献类型：
--
作者：
H. Shen;H. Fehlman;C. Mendoza
许多以前的研究表明，总电阻分为皮肤电阻和形式电阻没有直接的证据。在这项研究中，皮肤阻力，形式阻力，和总阻力独立测量一系列的刚性床形式在实验室中。数据显示，对于所进行的所有实验运行，表面阻力和形状阻力的总和接近于总阻力。此外，本研究和其他研究中收集的数据表明，可以根据已知的河床形状预测形状阻力。Darcy-Weisbach形状因子和压阻系数仅与沙丘的相对高度有关，与流速无关。冲积层形态阻力的变化规律与管道中的膨胀损失相似。基床表面阻力对同一基床的形式阻力影响不显著。测得的局部皮肤应力几乎线性增加，从零值在流动再附着点的沙丘顶部的最大值。推导出的关系来预测的皮肤阻力作为一个函数的流动雷诺数，相对粗糙度，和相对高度的沙丘的基础上收集的数据在本研究和其他研究。对非均匀床面的表面阻力和形状阻力也进行了测量和分析。
Many previous studies suggest the division of total resistance into skin resistance and form resistance without direct evidence. In this study, the skin resistance, form resistance, and total resistance are independently measured for a series of rigid bed forms in the laboratory. The data shows that the sums of skin resistance and form resistance are close to the total resistance for all experimental runs conducted. Furthermore, data collected in this and other studies indicate that form resistance can be predicted from known bed form shapes. The Darcy-Weisbach form factor and the pressure drag coefficients are related only to the relative height of the dunes and independent of the flow velocities. The variations of form resistance for alluvial bed forms are similar to the expansion losses in pipelines. Skin resistance on the bed form has no significant effect on form resistance of the same bed form. The measured local skin stress increases almost linearly from a zero value at the flow reattachment point to a maximum value at the dune crest. A relationship is derived to predict the skin resistance as a function of flow Reynolds number, relative roughness, and relative height of dunes based on data collected in this and other studies. The skin and form drag for nonuniform bed forms are also measured and analyzed.