Cyber-physical flexible wing for aeroelastic investigations of stall and classical flutter

Nonlinear flow-induced instability of an elastically mounted pitching wing

“…The non-dimensional fluid torque, τ * f , is the unsteady moment coefficient of the wing. Another important non-dimensional parameter in the present study, which has appeared in many previous FSI studies (Khalak & Williamson 1996;Kim et al 2013;Fagley et al 2016;Menon & Mittal 2019), is the non-dimensional velocity U * , defined as U * = U/(2πfc), where f is the oscillation frequency. It is important to note that U * can have different definitions in the present study, depending on the frequency used to calculate U * .…”

“…Cyber-physical systems have been employed in several previous experimental studies for researching fluid–structure interactions (FSI), including VIVs (Hover, Miller & Triantafyllou 1997; Lee, Xiros & Bernitsas 2011; Mackowski & Williamson 2011) and passively pitching wings (Onoue et al 2015; Fagley, Seidel & McLaughlin 2016; Su & Breuer 2019). These systems combine a cyber system and a physical system to experimentally simulate the kinematics and dynamics of elastically mounted objects.…”

“…The cyber system is a feedback control network that takes in the physically measured system kinematics – e.g. force (Hover et al 1997; Mackowski & Williamson 2011; Su & Breuer 2019), velocity (Lee et al 2011; Onoue et al 2015) and displacement (Lee et al 2011; Fagley et al 2016) – and calculates in real time the corresponding system response based on the virtual structural properties defined by the user. The physical system usually consists of an actuator, which receives and executes the system response signal from the cyber system, and a sensor, which measures the system kinematics again at the next moment and sends it back to the cyber system.…”

Vibration control of cantilever blade based on trailing-edge flap by restricted control input

“…However, the edge-wise bending behavior should be taken into account if the stall-induced state is to be studied, then the quasi-stable aerodynamic force is no longer applicable and should be replaced by the aerodynamic force under the stall condition. 6…”

“…The fluid-structure interaction of a finite aspect ratio, cantilevered, flexible wing was investigated using a cyber-physical system to virtually augment the twist dynamics of the wing, with a sectional view of NACA0018 cyber-physical wing mounted on the wind tunnel experimental subfloor to study the flutter of 3D structure. 6 Due to modeling uncertainty, which is an important, non-negligible issue in analysis of coupled-mode flutter of long-flexible rotating blade, the stochastic flutter problem of 3D blade was investigated by Li and Caracoglia 7 to understand the influence of uncertainty in selected input characteristics, with the classical aerodynamic model derived from Theodorsen theory.…”