Christy Ushanth Navaratnam, Jochen Aberle, Pierre-Yves Henry
Hydropower tunnels represent an important feature in Norwegian hydropower systems. They are used for the transport of water from reservoirs for power production and to provide the controlled release of flood flows from reservoirs. The quantity of water that can be conveyed through a tunnel depends on its friction, and many of the Norwegian hydropower tunnels are unlined, i.e. the tunnel walls are left untreated after excavation. The friction caused by rough tunnel walls is generally quantified by empirical approaches, tabulated values, or photographic methods.
This thesis is affiliated with the research project TunnelRoughness and laboratory experiments on scaled models of Norwegian hydropower tunnels. The aim of the thesis is to determine the energy losses in the scaled models and investigate the hydrodynamics, in particular, the turbulent flow field obtained from Particle Image Velocimetry (PIV).
(a) A view into a milled tunnel with access widows for PIV measurements, (b) & (c) Visual impression from PIV measurements (Photos: Pierre-Yves Henry and Christy Ushanth Navaratnam)