Measuring the hydraulic effect of hydrokinetic energy extraction in the Tanana River, Alaska

Abstract

During two field seasons, a 1.93 m diameter, open-center style, hydrokinetic device was deployed from a pontoon barge in the Tanana River, in Alaska. Near-surface velocity was roughly 1.7 m/s and 2 m/s at the deployment site during September 2014 and July 2015, respectively. Velocity and turbulence were measured in the vicinity of the turbine location using an acoustic Doppler velocimeter (ADV) and an acoustic Doppler current profiler in order to characterize the impact of the turbine on river hydraulics and turbulence. ADV measurements showed velocities being 97.8% recovered within 18.1 turbine diameters and fully recovered within 20.7 turbine diameters. ADV measurements also indicate a 520% increase in turbulence intensity at 2.6 turbine diameters downstream which appeared to resolve within 20.7 turbine diameters.