Discharge Coefficients for Sluice Gates Set in Weirs at Different Upstream Wall Inclinations

Abstract

Laboratory experiments and numerical simulations are performed to measure discharge coefficients in the case of a gate located on the upstream wall of a weir for flood storage. The effect of the gate slope and the side contraction have been taken into account. The study was first performed experimentally, when three series of tests were carried out with (and without) a broad crested weir located under the gate, at different values of the inclination angle of the weir upstream wall, and at different values of the shape ratio and the relative opening. In order to provide useful suggestions for those involved in sluice gate construction and management, three equations were obtained based on multiple regression, relating the discharge coefficient to different parameters that characterize the phenomenon at hand, separating the case when the broad-crested weir was present. Then numerical simulations were executed by means of the Reynolds-averaged Navier–Stokes (RANS) equations with the k-ε turbulence closure model and in conjunction with the volume of fluid (VOF) method, to validate the numerical results against the experimental and to possibly investigate phenomena not caught by the experimental measurements. Simulated discharges were very close to the observed ones showing that the proposed three-dimensional numerical procedure is a favorable option to correctly reproduce the phenomenon.

Porous Medium Typology Influence on the Scaling Laws of Confined Aquifer Characteristic Parameters

“…The initial undisturbed hydraulic head varied between 0.32 m and 0.38 m to ensure that the confined formation remained under pressure, and the complete restoration of the initial loading conditions between tests was always verified [28,29]. In order to measure head changes during the slug tests, 10 submersible transducers, model Druck PDCR1830 (for more details, see [30][31][32]), were positioned at the bottom of each well. The pressure data were recorded using a measurement frequency of 100 Hz and filtered using the Mexican hat wavelet transform to eliminate the experimental high-frequency noise, as suggested by the authors of [28].…”

Flow Resistance in Open Channel Due to Vegetation at Reach Scale: A Review

“…For a detailed analysis of the flow fields and turbulence characteristics, one can refer to measurements with a particle image velocimetry system (PIV) or acoustic Doppler velocimeter (ADV) probe or, furthermore, on numerical simulations, more or less detailed depending on the flow cases at hand [65,[112][113][114][115]. An excellent review about the numerical models utilized for the analysis of the interaction between flow and vegetation is due to Stoesser et al [116], and one can refer to this work for a systematic view of the different aspects of this matter.…”

“…The author gives, for every class of channels, the minimum, average, and maximum values of Manning n coefficient, warning that when the channel is artificial, the average values should be used in case of good maintenance only. In Tables 5 and 6 of Chow's book ( [47], p. [110][111][112][113], one can observe that the Manning coefficient is 0.018 sm −1/3 in case of the excavated channel, straight, clean, uniform cross-section with no vegetation, and 0.035 sm −1/3 in case of dense weeds. In natural streams, its values are 0.030 sm −1/3 when the cross-section is clean, and 0.045 sm −1/3 in case of weeds.…”

Experimental and Numerical Study of the Effects of Geometric Appendance Elements on Energy Dissipation over Stepped Spillway

“…The RNG k-ε was proposed by Yakhot and Orszag [41] and represents a modified version of the k-ε standard model. In particular, the RNG k-ε turbulence model has an additional term in its ε equation (see successive Equation ( 14)) that improves the accuracy for quickly strained and swirling flows and also has good accuracy based on the results of numerical investigations by Bayon et al [28], Daneshfaraz et al [35], Ghaderi et al [42], Lauria et al [43], Ghaderi et al [44] and Pourshahbaz et al [45]. The adopted turbulence scheme is a two-equation model that is expressed as:…”