Mean flow and turbulence statistics through a sluice gate in a navigation lock system: A numerical study

Abstract

The flow through partially-open control valves in navigation locks, particularly at the early portion of an operation cycle, is characterized by high velocities, flow recirculation, significant pressure drops, and pressure fluctuations within the culverts. Optimizing the flow control system is a key point in hydraulic projects of high-drop locks. In order to analyze the hydraulic parameters of the mean flow and turbulence statistics through a navigation lock control valve, experimental and numerical work was undertaken. This paper focuses on the numerical aspects of the research. A physical model with a rectangular culvert (25 cm x 25 cm) test section with a segment gate (Tainter) installed in its inverted position was used in the experimental research. Physical tests were carried out under steady conditions for six gate openings and nine discharges. During these tests, mean and instantaneous pressures were recorded along the base and the ceiling of the culvert. The numerical investigation was carried out using the Computational Fluid Dynamics (CFD) software FLOW- 3D®. In FLOW- 3D®, the Reynolds-Averaged Navier–Stokes (RANS) equations were solved by the methods of finite volumes/finite differences in two dimensions. To solve the problem of closing RANS equations, the turbulence model k−ε was adopted. Based on the results, it was possible to verify that the numerical model very nicely reproduced the behavior of experimental data of mean hydraulic head and mean flow velocities. Although along the culvert ceiling, particularly close to the gate, the drop in mean pressure was slightly underestimated by the numerical model at the flow recirculating zone, it is possible to state with confidence that the overall results underscore the accuracy of this CFD approach in the study of the mean flow downstream from the control valves in navigation lock filling–emptying systems.