Numerical study of the shapes of circular and d-shaped cross sections of the tunnel spillway using ansys (fluent) and flow3d software products.

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Tuesday 30 june 2015

12:36 - 12:39h at Europe 1 & 2 (level 0)

Themes: (T) Water engineering, (ST) Computational methods, Poster pitches

Parallel session: Poster pitches: 5E. Engineering - Computional

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Nowadays, tunnel spillways are used in situations where positioning an open spillway is not feasible due to excessive excavation or some technical issues with the project. The spillway designing is based on the Discharge Flood and the Difference of head of upstream and downstream, accordingly by creating a steep gradient, the flow of flood develop as a supercritical flow throughout the tunnels consequently, thus we can see an increasing of the speed and reduce the depth of flow and the tunnel cross section is reduced finally. Tunnel section should be considered in such a way that sufficient space for free-surface flow throughout the tunnels is available, in addition to satisfying the complete process of aeration to reduce the risk of cavitation, The shape of dimensions of the cross section such as that we can ensure the health of the spillway during the operation. the executive aspects of cross sections of the tunnel spillway is also important that it related to the excavation and lining methods. In this study, we tried to investigate on the hydraulic aspects of this kind of spillways with circular and D-shaped sections in both the upstream and downstream slopes using Computational Fluid Dynamics (CFD) and flow simulation with numerical models using Flow 3D and ANSYS (Fluent) software products. In general, the numerical analysis on case study of Rudbar dam's spillway tunnel was observed, that both types of cross sections, in certain conditions, including: the performance, design discharge and the Difference of head of spillway relative to other cross section, is preferable.