Investigating velocity fluctuation by means of ADV at compound channel with installed hydropower propeller turbines.

Abstract: An acoustic Doppler velocimeter (ADV-FlowTracker 2) was used to measure the velocity field in three different positions in the Biffis channel. The channel is a regulated compound concrete channel continuously diverting 130-135 m3/s from the Adige River (Italy) for irrigation. Three different experiments were conducted with three different hydraulic conditions (turbines in production or off). Turbulent fluctuations are key factors in entrainment of the sediments from the bank surface. This campaign aimed to evaluate capability of the ADV to examine the influence of the of propellers turbines (prototypes) on the free surface channel flow, the velocity fluctuations and to identify presence of coherent structures. The results showed that the velocity fluctuations related to the channel geometry are present in all measurements regardless of the active turbines. However, the turbulent kinetic energy, the length and the number of the turbulent events are larger for the cases when the turbines were in production. The turbulent events are shorter for the case in which both turbine-arrays worked.     «

Abstract: An acoustic Doppler velocimeter (ADV-FlowTracker 2) was used to measure the velocity field in three different positions in the Biffis channel. The channel is a regulated compound concrete channel continuously diverting 130-135 m3/s from the Adige River (Italy) for irrigation. Three different experiments were conducted with three different hydraulic conditions (turbines in production or off). Turbulent fluctuations are key factors in entrainment of the sediments from the bank surface....     »