复式河槽动能损失强度分析

在复式河槽中，由于滩槽交界面存在强烈的动量交换，使得复式河槽过流能力降低。为了反映动能损失的强度，针对恒定、均匀、紊动水流，提出了横向动能校正系数和动能损失率的概念。通过分析复式河槽动能损失的机理发现：在复式河槽中，横向动能校正系数大于1和动能损失率大于0。分析英国科学工程研究委员会洪水水槽设施的系列试验成果，发现横向动能校正系数和动能损失率与复式断面形态有关。动能损失强度随着主槽边坡系数的增大而减弱，随着滩槽宽度比的增大而增强。对称复式河槽的动能损失大于非对称的复式河槽。对于所有断面形态，动能损失强度先随相对水深的增加而增强，后又随着的相对水深的增加而减弱，最终表现出单一河槽的特性。

Analysis of Kinetic Energy Loss Intensity in Compound Channels

The intense momentum transfer on the vertical interface between main channel and flood plain in a compound channel, makes its conveyance capacity decrease. To reflect the kinetic energy loss intensity in a compound channel, two new concepts, transverse kinetic energy correction coefficient (TKECC) and kinetic energy loss rate (KELR) are put forward for steady, mean and turbulent flow.Through the analysis of the mechanism of kinetic energy loss in compound channels, a conclusion is drawn that TKECC is larger than 1 and KELR is larger than 0 in compound channels.By analyzing the experimental data from Science and Engineering Research Council-flood Channel Facility (SERC-FCF), it is found that TKECC and KELR are both related to shapes of cross section. Kinetic energy loss becomes weaker with main channel side slope factor increasing and becomes stronger with the ratio of main channel and flood plain width increasing. Kinetic energy loss in a symmetric compound channel is stronger than that in an asymmetric one. For all the shapes of cross section, kinetic energy loss increases with the relative depth increasing. After it reaches the largest value, it decreases with the relative depth increasing, and the compound channel ultimately shows a characteristic of single channels.