Author(s): Zhichang Zhang; Ying Zhao; Minghuan Fu; Ruobing Li
Linked Author(s):
Keywords: Hydraulic jump; Water head loss; Resistance coefficient; Boundary layer
Abstract: In 1965, Rajaratnam has put forwarded new concept that hydraulic jump is a kind of wall jet. According to mixed flow theory, Guo Zizhong holds that hydraulic jump is an attached wall jet affixed to the bottom in 1982. This new concept proposed opens new avenues for the research on hydraulic jump characteristics. The study considers that although the surface in hydraulic jump area has spin, the mainstream is still at the bottom, and the development of boundary layer below the region of maximum flow velocity remains consistent with the turbulent boundary layer theory, so the turbulent boundary layer development of hydraulic jump region can be discussed by adopting the momentum integral equation of turbulent boundary layer. Starting from this concept, this paper analyzes the research results of Rajaratnam about velocity distribution, the maximum velocity distribution along the way, wall shear stress and proposes the calculation method of the thickness of turbulent boundary layer and kinetic energy loss; It obtains the distribution law of frictional head loss and the calculation method of frictional head loss in hydraulic jump region; According to the definition on local resistance, it also studies local resistance coefficient in hydraulic jump region and gives the calculation formula of local resistance coefficient. The results shows that frictional head loss increased with the increase of frictional head loss, the speed of the flow, length of jump and kinematic viscosity coefficient；Local resistance coefficient which is mainly a function of the Froude number 1Fr increases with the increased Froude number. And the hydraulic jump head loss mainly for the local head loss is confirmed by calculation example.
Year: 2013