Experimental and numerical investigation of propagation of flood waves due to dam break

The distorted physical model of Ürkmez Dam was constructed together with its reservoir and the downstream part. The horizontal and vertical scales of the model are 1/30 and 1/150, respectively. The model was constructed by means of the maps and drawings obtained from State Hydraulic Works (DSI) and current digital layout plan obtained from the General Directorate of Water and Sewerage Administration (IZSU). Seferihisar - Kuşadası highway and residences were reflected in the model together with the relevant topography. Water depths were measured by using e + WATER L level meters. Velocities were determined with Ultrasonic Velocity Profiler (UVP) sensors. The propagation of the flood wave was recorded by high definition camera. Numerical analysis was performed by means of Flow 3D software by using RNG, LES and k-ε turbulence models. The experiments were carried out with three different scenarios and the magnitudes of the maximum water depths were observed in the following order: sudden collapse, formation of trapezoidal breach and formation of triangular breach. The shortest time to reach the maximum depths was observed in the sudden collapse case and followed by trapezoidal and triangular formation cases. In the experiments, water depths up to 12 cm were measured. This value corresponds to 3.6 m meaning that the residences of one floor will be submerged. The velocities measured in the experiments reached 6 m/s, which corresponds to a speed of 32.88 m/s in nature. Such velocities are large enough to threaten the stabilities of the structures because of significant hydrodynamic effect. During the experiments the time elapsed for the flood wave to reach the intense residential area is about 6 seconds, which corresponds to 2.7 minutes in nature. In the experiments, the flood wave reached the highway approximately in 7 seconds, which corresponds to 3.2 minutes in nature. It was revealed that numerical results obtained by using RNG turbulence model was more compatible with the experimental findings.