Numerical study on gust energy harvesting with an efficient modal based fluid-structure interaction method

Abstract

Gust disturbance during flight causes elastic vibrations and rigid body motions of an aircraft. A macro fiber composite (MFC)-based energy harvester can be used to obtain energy from gust-induced vibrations. This paper aims to present an efficient fluid-structure interaction (FSI) method for fast and accurate calculation of gust response and harvested energy of a fly wing aircraft half model. In this method, computational fluid dynamics (CFD) and computational structural dynamics (CSD) are coupled by embedding a modal-superposition-based structural solver into the CFD solver. Parallel data exchange and interpolation strategy on the fluid-structure interface is introduced to improve the computational efficiency. MFC harvester is modeled by a piezoelectric beam model, and the displacement of the piezoelectric beam is obtained by interpolation from FSI results. The numerical results of gust response and MFC voltage output are in good accordance with wind tunnel test results, while the calculation time is only 1/8 of the time consuming of a direct CFD/CSD coupling method. The influences of gust frequency, gust amplitude, freestream velocity, and the number of retained modes on energy harvesting are investigated. Results indicate that the accuracy of the calculation can be guaranteed by the superposition of several retained modes, and the additional suction provided by leading-edge vortices causes a nonlinear increase in energy harvesting near the stalling angle of attack.