Numerical simulation of supercritical flow in sudden contractions flumes

Abstract

In this research, the effect of sudden non-continuous contraction on the energy dissipation of supercritical flows was numerically investigated. This study focuses on energy dissipation in sudden contractions in supercritical flows. The numerical models were studied using FLOW-3D software and the random number generator (RNG) turbulence model. The laboratory tests were performed on sudden contractions of 10–15 cm and used shapes such as geometric trapezoidal and semicircular. Numerical simulations were carried out at a distance of 1.5 m from the supercritical flow generator gate, at a fixed opening of 2.6 cm, with the Froude number in the range of 2.5–7 and the relative contraction in the range of 8.9–9.73. This laboratory study found that as the Froude number of the upstream flow increases, the energy dissipation increases in the upstream (ΔE/E0) and downstream (ΔE/E1). For the 15 cm contraction, the results indicated that the energy loss compared with section A is 48.25% and compared with section B, it is 69.5% more than a free hydraulic jump in this channel. According to the conclusion, this value in trapezoidal constriction is 45.73 and 63.6% higher than in free hydraulic jump, respectively.