Numerical simulation of ow over labyrinth spillways

Spillways play an important role in the safety of dams. To ensure the safety of dams, spillways should be designed considering oods with long return periods. To increase the discharge capacity of a spillway, a designer can increase the crest length using the labyrinth spillway. For high head conditions, the local submergence may decrease the eciency of a labyrinth spillway. In this study, the hydraulic characteristics of linear and arced labyrinth spillways are compared, and the eect of the downstream bed level on the discharge coecient of labyrinth spillways is studied numerically. The numerical simulations are done using Flow-3D software. RNG k ?? " model is used for turbulence simulations and the free-surface proles are calculated by VOF method. Experimental data of pervious researchers are used for validation of the proposed numerical model. The results show that in the high head conditions, lowering the downstream bed level of a labyrinth spillway increases its eciency, especially in the case of an arced labyrinth spillway