Unsteady Wake Effects on Power Generation in Oscillating Foil-Arrays

A predictive model is developed to quantify the effects of wake-foil interactions in the performance of oscillating foils arrays for energy harvesting. The wake dynamics behind flapping foils is particularly important since the coherent structures can cause constructive and/or destructive interference with downstream foils. This work numerically explores a wide range of foil kinematics and array configurations, with the goal of quantifying the power generation difference between foils affected by different wake structures. Due to the wake deficit caused by the leading foil, the power generation from downstream foils are normalized by an averaged wake velocity, then compared directly with the baseline power generation profile. The difference between the time averaged power curves represents the effects of the unsteadiness in the wake. This data is used to build a predictive model for downstream foil performance and hence provide insight for optimizing foil arrays configurations for energy harvesting.