Underflow Curvature and Resultant Force on a Vertical Sluice Gate

Abstract

Sluice gates are an important component of many hydraulic engineering systems; they have been extensively used to regulate reservoir water levels and to measure discharges. This paper reported new experimental and computational results of underflow passing below a vertical sluice gate. The focus was on the flow curvature immediately downstream of the gate and the associated centripetal force on the gate lip. The experiments and computations covered gate openings of 2.54–40.64 cm, and ratios of upstream flow depth to gate opening of 4–16. The computations successfully produced the two-phase (air–water) flow field from solving the Reynolds-averaged Navier–Stokes equations. The computed flow profiles and the distribution of pressures compared well with the experimental results. We recommend the shear stress transport k-ω model for turbulence closure and the volume of fluid (VoF) method for efficiently tracking the highly curved free surface. Analyses of the experimental and computational results led to the development of useful expressions for key flow-curvature parameters, including the radius and center of the circle of curvature, and the angle of a tangent to the free surface with the channel bottom. The curvature is maximum immediately downstream of the lip and decays farther downstream. Curvature-induced forces on sluice gates at hydroelectric power generating stations were determined. In addition, this paper proposed corrections to some existing formulations of the underflow problem and updated the contraction distance and coefficient.