Uniqueness of discharge coefficient of sluice passage for tidal power plant: CFD modelling

Abstract

The discharge coefficient (C_d) of the sluice passage in tidal power plants is an important index targeted by many tidal power studies aiming to improve the discharge capability of the sluice passage and, thus, the efficiency of tidal power generation. In this work, the discharge capability of the two most common types of sluice passages (i.e., Venturi- and culvert-type passages) was analysed and compared through the Computational Fluid Dynamics (CFD) simulations using Flow 3D. The results of this study clearly demonstrated the uniqueness of the discharge coefficient i.e., the C_d values estimated for each of the Venturi and culvert passages were constant irrespective of the position of cross sections selected along the passage. Most importantly, unlike previous results, the C_d values estimated at the throat and outlet sections for the Venturi passage were the same. The mean C_d values for the Venturi and culvert passages were about 0.8 and 0.91, respectively, with maximum relative differences of 4.9 % and 3.2 %, respectively, indicating superior discharge capability of the culvert passage over the Venturi one. It is believed that the present results will help researchers and engineers accurately estimate and improve the discharge capability of sluice passages for tidal power plants.