Aeroelastic simulation of torsional vibrations in a single-axis solar tracker

Abstract

Wind-induced torsional vibrations in a single-axis solar tracker (SAST) are simulated by coupling a structural displacement solver with delayed-detached eddy simulation (DDES) of the turbulent crossflow. The resulting amplitude-frequency response is reported across an operational range of reduced wind velocities at various orientations. This investigation aims to offer a cost-effective, agile alternative to wind-tunnel testing for SAST development. Based on validated fluid-elastic modeling practices, the work focuses on predicting the torsional galloping instability, as observed in earlier experimental research. The solutions confirm the onset of torsional instability for certain SAST orientations at critical reduced velocities in agreement with peer measurements. Moreover, two markedly different aeroelastic behaviours are categorized, labelled as the vortex-asynchronous and vortex-synchronous vibration regimes. Spectral analysis reveals that self-excited vibration is triggered by synchronization between the frequencies of vortex shedding and torsional vibration. The normalized work performed on the structure is computed, demonstrating a net energy influx per cycle from flow to structure during the galloping phenomenon. Ultimately, the adopted methodology serves as a viable and inexpensive test bed for the expedite prediction of aeroelastic response in SASTs. The automated control of design parameters and rapid computational turnaround can significantly streamline the wind design of open solar structures.