Mosquitoes of the species Aedes Aegypti exhibit a particularly distinctive figure-eight shaped wingtip trajectory, which includes a vertical component of motion (characterized by deviation angle) that is hypothesized to influence aerodynamic force generation through interactions with the wing’s own wake, referred to as wake capture. While standard quasi-steady (QS) aerodynamic numerical models can effectively predict the forces generated by translational, rotational, coupling and added mass effects during wing motion, they do not capture the additional forces arising from wake interaction.

This study aims to leverage this known limitation of quasi-steady models, to investigate the influence of deviation angle on wake capture forces during hovering flight. Aerodynamic forces were measured using a robotic flapping-wing apparatus programmed to replicate biologically plausible kinematics of a mosquito, across a range of deviation angles (0° - 6°) (including an outlier at 7.5°). By subtracting forces predicted by a validated quasi-steady model from the experimentally measured forces, the residual unsteady component associated with wake capture was isolated and quantitatively analyzed.

The results of this study demonstrated that wake capture forces play a beneficial aerodynamic role in the mid-to-high deviation angle range, specifically between approximately 4° and 6°. Within this interval, the wake capture lift and drag forces exhibit relatively elevated mean values, and the experimentally observed lift-to-drag ratio surpasses quasi-steady predictions, indicating enhanced aerodynamic efficiency. Correspondingly, power utilization increases, and flapping efficiency peaks near 5° to 6°, collectively highlighting an optimal regime where unsteady wake interactions benefit aerodynamic performance. This favorable trend could be attributed to the pronounced out-of-plane wing motion at these deviation angles, which intensifies three-dimensional wake structures and possibly promotes more effective wing-wake vortex interactions that augment lift and overall flapping efficiency.

In spite of the high uncertainty in the force sensor readings, this study successfully established a kinematically accurate, high-fidelity setup for examining the influence of deviation angle on wake capture phenomena. The elevated noise from the inbuilt force sensor and structural vibration in the wing assembly were identified as the primary limitations, which could only be fully resolved through hardware replacement beyond the present scope. Nevertheless, the findings provide novel insights into the role of deviation angle in shaping wake capture forces, with both scientific implications for advancing flapping-wing micro air vehicle (FWMAV) design and societal relevance given the connection between mosquito flight and public health.