Theoretical and Numerical Analysis of the Pressure Distribution and Discharge Velocity in Flows Under Inclined Sluice Gates

Abstract

Abstract The flow under sluice gates is nowadays frequently still determined by empirical approaches, based on the Bernoulli equation and a specific discharge coefficient which depends on the geometry of the sluice gate. This discharge coefficient is determined either from potential theory approaches or from a variety of experimental series. Based on Malcherek’s new momentum balance theory approach, the flow under inclined sluice gates can be described now on a physical approach. While the pressure distribution of the vertical sluice gate, which was investigated by the authors in previous works, results in a horizontal acting force only, the pressure distribution of the inclined sluice gate brings an additional force component acting in the vertical direction. The magnitude and the sign of the force in the vertical direction depends on the sign and the value of the angle of inclination. With the commercial CFD solver Star-CCM+ from Siemens PLM, the flow under inclined sluice gates was investigated in detail, to be compared with Malcherek’s momentum balance theory. For this basic investigation, boundary layer effects and 3D effects were first neglected. For various angles of inclination and water levels the pressure distribution on the ground under the sluice gate and on the surface of the sluice gate itself, were evaluated and mathematical functions were introduced to describe the pressure distributions. These results were compared with the results from the vertical sluice gate. Also the discharge velocity and the volumetric flow rate were analyzed and compared with the Malcherek’s new momentum balance theory for inclined sluice gates.