Theoretical bend-flow solutions and velocity-dip phenomenon

ABSTRACT

Flow structure in an open-channel bend exhibits two specific features: (1) secondary flow caused by the channel curvature; and (2) typical occurrence of the maximum velocity below the water surface, known as velocity-dip phenomenon. To explain these features, this paper proposes a coupled model that provides theoretical three-dimensional bend-flow solutions. Considering the transverse distributions of hydraulic parameters as non-uniform and influenced by the side-wall stresses, the complete secondary circulation is obtained theoretically. Using a modified log-wake law, the velocity-dip phenomenon is analysed and found to exist in both primary and secondary flows.

Keywords:

• Analytical solutions
• bend flow
• modified log-wake law
• open channel
• velocity-dip phenomenon
• velocity distribution

Additional information

Funding

This work was partly supported by the National Natural Science Foundation of China [grant 51279124, 51321065, 51021004, 51009105] and Jiangxi Province Water Conservancy Science and Technology Project (Major Project) [grant 2014GKF-0855].