Large eddy simulation of flow around semi-conical piers vertically mounted on the bed

Abstract

In this paper, details, and results of three-dimensional numerical modeling of flow around the semi-conical piers vertically mounted on the bed in a channel, are presented. For flow simulation, 3-D Navier-Stokes equations are solved numerically using the finite volume method and large eddy simulation (LES). In this study, the semi-conical piers with different side slope angles are tested, and the flow around them is compared with the cylindrical reference pier. Flow structures, vortex shedding behind piers, horseshoe vortices, instantaneous and time-averaged flow structures are presented and discussed. Numerical model results show that the semi-conical piers are eventuated remarkable reduction (up to 25%) in downward flow velocity in the upstream side of the piers, and much more reduction (up to 46%) in bed shear stresses in comparison with the cylindrical pier. Moreover, the model results showed some decrease in vortex shedding frequency for the semi-conical piers compared to the cylindrical pier.We report on numerical results of large eddy simulation of the flow around semi-conical piers with different side slopes. This research is significant because of the effect of these piers on the:reduction of the downward flow and the bed shear stress around the piers.reduction of vortex shedding frequency for the semi-conical piers compared to the cylinder.different behavior of the horseshoe vortices at the upstream compared to the cylinder.

Characteristics and Hazards Analysis of Vortex Shedding at the Inverted Siphon Outlet

“…The CFD method has the advantages of lower costs and higher efficiency than the experimental method. Aghaee et al [17] successfully simulated the flow around a semi-conical pier in the channel bed by a numerical method. Park et al [18] simulated the wake behind the square column with the standard k − ε and RNG k − ε turbulence models, and the comparisons of simulation and theory showed that the errors of maximum velocity difference and the drag coefficient ratio were less than 4% when using the RNG k − ε model.…”