不透過越流型水制周辺の三次元乱流構造に及ぼす水制設置角度の影響

概要

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3D turbulent flow structures around sub-merged inclined spur dikes are numerically investigated. The basic equations of the numerical model are derived on a generalized curvilinear movable coordinate system with full-staggered arrangement of hydraulic variables. A 2nd order non-linear k-ε model with effects of the strain parameter and the rotation parameter is adopted as a turbulence model to simulate the complex turbulent flows with separation and vortex shedding from the edge of the spur dikes. Numerical results are compared with the results in the PIV measurements by Tominaga et al (2001) and the model performance is examined. The present numerical model could reproduce the fundamental aspect of the 3D turbulent flow features influenced by the inclination angle of the spur dikes. The effects of the inclination angle are clarified in both the averaged flow patterns and the fluid oscillations. In time averaged flow fields, the flow from the bank toward the main flow is dominant around the downstream inclined spur dikes while the reverse flow is dominant around upstream inclined ones at the vicinity of the bed. The amplitude of the fluid oscillation around the downstream spur dikes is much larger than that around the upstream ones. The period of the fluid oscillation is in compatible with the first mode in the impinging shear layer.
四日市大学の論文
2002-09-30