3-D underflow of a sluice gate at a channel inlet - Experimental results and CFD symulations

The underflow of a sluice gate is well known when the gate is set into a channel of the same width (2-D underflow), while no studies are found in the literature when the gate is flush with the wall of the tank or reservoir upstream to the channel (3-D underflow). Experimental and numerical investigations were carried out to study the flow in this case, in small range of relative opening, considering three wall slopes, and obtaining an equation for the discharge coefficient. Afterwards, numerical simulations were performed by means of a CFD (Computational Fluid Dynamics) model, following the RANS approach and based on a finite-volume computational code. Comparison of experimental and numerical results showed that the simulations predict accurately the flow behaviour; thereafter discharge coefficients in a more extended range of relative openings were computed for use in the practice.