Energy Dissipation and Hydraulics of Flow over Trapezoidal–Triangular Labyrinth Weirs

Abstract

In this work experimental and numerical investigations were carried out to study the influence of the geometric parameters of trapezoidal–triangular labyrinth weirs (TTLW) on the discharge coefficient, energy dissipation, and downstream flow regime, considering two different orientations in labyrinth weir position respective to the reservoir discharge channel. To simulate the free flow surface, the volume of fluid (VOF) method, and the Renormalization Group (RNG) k-ε model turbulence were adopted in the FLOW-3D software. The flow over the labyrinth weir (in both orientations) is simulated as a steady-state flow, and the discharge coefficient is validated with experimental data. The results highlighted that the numerical model shows proper coordination with experimental results and also the discharge coefficient decreases by decreasing the sidewall angle due to the collision of the falling jets for the high value of H/P (H: the hydraulic head, P: the weir height). Hydraulics of flow over TTLW has free flow conditions in low discharge and submerged flow conditions in high discharge. TTLW approximately dissipates the maximum amount of energy due to the collision of nappes in the upstream apexes and to the circulating flow in the pool generated behind the nappes; moreover, an increase in sidewall angle and weir height leads to reduced energy. The energy dissipation of TTLW is largest compared to vertical drop and has the least possible value of residual energy as flow increases.

Investigation of Local Scouring around Hydrodynamic and Circular Pile Groups under the Influence of River Material Harvesting Pits

“…A turbulence model is needed for additional modeling of the nonlinear Reynolds stress term. Some numerical studies have proposed the Reynolds-Averaged Navier-Stokes (RANS)-based k-omega and the Renormalization Group (RNG) k-ε [28][29][30][31][32][33][34][35][36][37] and LES (large eddy simulation) models [38][39][40] for the scouring problem. The LES turbulence model was used to perform computation of fluid dynamics (CFD).…”

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

“…According to Figure 4, the tests were carried out in a rectangular flume with a length of 12 m, a width of 1.2 m, and a height of 0.8 m. The flume had glass walls (to improve flow visibility and reduce friction) and a steel floor. With plexiglass, the influence of sidewall effects is considered to be negligible (see Johnson [32] and Ghaderi et al [33]). The slope of the flume is adjustable by a hydraulic jack; however, for this study, the slope was set to zero for all experiments.…”

‪Impulse wave generation: a comparison of landslides of block and granular masses by coupled Lagrangian tracking using VOF over a set mesh

“…The relevant equations of motion include conservation of momentum, the continuity equation, and the phase fraction equation in their incompressible form, respectively provided by (Liu et al 2005;Ding et al 2007;McDonough 2009;Bedram & Moosavi 2012;Ghaderi et al 2020aGhaderi et al , 2020b:…”