Three-dimensional numerical modeling of water flow in a rock-blasted tunnel

Abstract

Climate change leads to more intense precipitation in Norway. NVE requires all bypass tunnels have sufficient capacity for bypassing flood water. The hydro-power industry needs a method for establishing tunnel capacity, such as computing a friction factor. Friction factor for rock-blasted tunnels have yet to be studied thoroughly. This thesis describes a method for finding friction factors for Litjfosstunnellen using numerical models. Three turbulence models are tested and compared; k-Epsilon, k-Omega and k-Omega SST. For otherwise identical setups k-Epsilon converges better than the other two. k-Epsilon yields larger Darcy friction factors than k-Omega and k-Omega SST in general. Grids with more cells yield larger friction factors than a coarse mesh (with one exception). Grid independence is not reached.