Flow field investigation by means of ADCP for the evaluation of hydropower propellers installed at open channel

The acoustic Doppler current profiler was applied in the Biffis channel that is a regulated concrete irrigation channel in the Adige River plain (Italy). This campaign aimed at evaluating the effects on the hydrodynamic field induced by propellers prototype installed for the hydropower exploitation. The reconstructed velocity maps and the spectral analysis of velocity time series in fixed positions made evident a convective acceleration close to the channel boundaries due to the operating propellers. This gave rise to flow velocities of about 1.6 m/s close to the channel concrete bed. Furthermore, within the wake of installed prototypes, velocity oscillations were observed within the entire investigated frequency range of 0.1-0.3 Hz.