Synchronization between a structure and surrounding flow during aeroelastic flutter

Aeroelastic flutter caused by the mutual interaction between surrounding flow and lift-generating structures of an aircraft has been studied for decades due to perils to life and property. Even though extensive research has been performed on this phenomenon, the complete mechanistic understanding of temporal and spatial synchronization between flow and structure, which leads to such dangerous large amplitude oscillations, continues to evade us. Analysis of the synchronization mechanism between the flow and structure is essential to understand the underlying physics and to design control strategies. In this experimental study, we use a multivariate complex network-based method corresponding to time series of fluctuations in strain (on a structure) and velocity fluctuations in a surrounding turbulent flow. A weighted cross recurrence network is used to analyze the interdependencies and coupling between them. Additionally, we calculate the correlation of probability of recurrence between velocity and strain to highlight the emergence of spatial and temporal synchronization as the system transitions towards flutter. Finally, we calculate the phase differences between these two variables in the region adjacent to the structure using the Hilbert transform to provide a causal relationship and the state of synchronization between the structure and the flow.