Author(s): Shao Xuejun; Wang Hong; Chen Zhi

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Keywords: Secondary flow; Compound channel; Reynolds stress model

Abstract: In curved open channels with a compound cross-section, secondary motion is driven by both the centrifugal force and turbulent stresses. In this study two Reynolds-stress models (RSM), i.e., models by Launder-Yang (LY model) and by Speziale-Yoshizawa (SY model), are used to calculate turbulence-driven secondary motion. The governing equation system is transformed into an orthogonal curvilinear coordinate system, so that the resulting equation set takes into account the effects of centrifugal forces. The numerical procedure is based on the SIMPLER scheme in an orthogonal curvilinear coordinate system. Various cross-section configurations and channel curvatures are used in the simulation using these models, and the impacts of different cross-sections and channel curvatures on the secondary motion are compared with measurements. The predicted secondary currents have been compared with published experimental measurements on a qualitative basis. Simulation results show that the LY and the SY models gives satisfactory reproduces the secondary flow features in a curved channel of compound cross-section. The longitudinal vortex pair were predicted at the region where the flood plain connects the main channel, and when the height of the flood plain changes, predicted the position and intensity of the vortex pair also varies, which agrees with experimental observations.

DOI:

Year: 2001