Abstract: A two-dimensional horizontal jet sediment erosion model is developed using a discrete phase model, to study the influence of sediment erosion on the energy extraction characteristics of a flapping hydrofoil. The results show that for the sediment diameter of 1mm, at a mass flow rate of 0.50kg/s and a flow velocity of 1m/s, the hydrofoil’s energy extracting efficiency reaches its peak of 44.9%, or an increase of 6.1% compared to the Kinsey’s peak of 38.8%. In sediment-laden flow, interaction is enhanced between the flapping hydrofoil and muddy water, leading to an increase in pressure difference, which is conducive to the hydrofoil’s fluctuating movement. Sediment-laden flow also accelerates vortex shedding in the wake of the hydrofoil with fierce disturbance on the trailing edge, so that the capability of capturing flow energy is enhanced. Therefore, the energy extraction characteristics of a flapping hydrofoil is improved by sediment-laden flow.

Key words: sediment erosion, discrete phase model, energy extraction efficiency, horizontal jet, flapping hydrofoil