Author(s): J. D. Nóbrega; J. Matos; H. E. Schulz; R. B. Canelas

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Keywords: Smoothed Particle Hydrodynamics; spillway; standing wave; supercritical flow; wall convergence

Abstract: Spillways may require converging sidewalls because of site or economy constraints. The adverse effects of the converging walls on supercritical flows include the formation of standing waves. In this context, numerical simulations were carried out using the Smoothed Particle Hydrodynamics (SPH) method. The numerical results were compared with experimental data acquired on a spillway model composed of a broad crested weir followed by a 1V:2H sloping chute with wall convergence angle of 9.9º or 19.3º, for a range of discharges. The flow depths at the spillway centerline were reasonably well predicted by the numerical simulations, except on the transition from the weir to the chute. Experimental data and numerical results showed that the sidewall flow depth normalized by the centerline flow depth (uninfluenced by the converging wall), tended to increase along the spillway, reaching maximum values of approximately 2 and 5, for wall convergence angles of 9.9° and 19.3°, respectively. Numerical cross-sectional flow depth profiles were also obtained, showing distinct shapes of the standing waves, depending on the wall convergence angle and position along the spillway. Overall, the simulated development of the standing wave width compared well with the experimental counterparts. The experimental velocity profiles obtained at the spillway centerline with wall convergence angle of 9.9º were also compared with those obtained numerically and the results revealed a fairly good prediction, except near the upstream end of the chute and close to the invert.

DOI: https://doi.org/10.26077/6b84-106d

Year: 2022