LAUSR

Abstract We investigated the displacement and lift time series of a circular cylinder - strip plate cruciform system for energy harvesting in the Reynolds number range 1.1 × 10 3 ≤ Re ≤ 14.6 × 10 3 , numerically using the open source C++ library: OpenFOAM. The Karman vortex-induced vibration (KVIV) regime was identified between reduced velocity, U * , 2.3 and 13.6, while the streamwise vortex-induced vibration (SVIV) regime was identified between 18.2 ≤ U * ≤ 29.5 . We analysed the cylinder displacement and lift time series using the Hilbert-Huang transform (HHT). Within this range of U * , Karman vortex shedding contributes nearly as much as streamwise vortex shedding to the root-mean-square amplitude of total lift, while between 25.0 ≤ U * ≤ 29.5 , the Karman component contribution is on average twice that of the streamwise component. These findings hint at the possibility to improve the power output of the harvester by a factor of two between 18.2 ≤ U * ≤ 22.7 and by a factor of three between 25.0 ≤ U * ≤ 29.5 , if we can unite the contribution to the root-mean-square amplitude of the total lift under a single vibration-driving mechanism: the shedding of streamwise vortex.