Author(s): Kari Bratveit; Oddmund Brevik; Nils Reidar Boe Olsen
Linked Author(s):
Keywords: Unlined rock-blasted sand trap; CFD; Turbulence models; Terrestrial laser scanner
Abstract: A well designed sand trap has a slow and uniform flow that enable sedimentation. The geometry and surface of an unlined sand trap excavated by rock-blasting is unstructured and rough, hence complex flow pattern can arise. In this study Computational Fluid Dynamics (CFD) was used to investigate the complex flow conditions that can occur in an unlined pressurized sand trap at the Tonstad Hydropower plant in Norway. A detailed three dimensional numerical model of the sand trap was established with a geometry based on point clouds obtained by a terrestrial laser scanner. The commercial CFD program STAR-CCM+ was utilized to compute representative velocity profiles for the sand trap. This numerical program was used to solve the Reynolds-Averaged Navier-Stokes equations in three dimensions. Different types of grids, discretization schemes and turbulence models were tested in order to optimize the simulation. Simulated velocity profiles were compared with results from field measurements performed by three submerged, rigidly mounted Acoustic Doppler Current Profiler (ADCP). The results presented in this paper shows reasonable agreement, indicating that the complex flow conditions arising in unlined structures can be predicted by three dimensional numerical simulations. This investigation shows that performance of the CFD calculations can be a useful tool during optimizing of sand traps.
Year: 2013