Sunghwan (Sunny) Jung, Cornell University
3/12/19
Fluids are vital to all life forms, and organisms presumably adapted their behaviors or features in response to mechanical forces to achieve better performance. In this talk, I will discuss two biological problems in which animals exploit mechanics principles. First, we investigated how animals transport water into the mouth using an inertia-driven (lapping) mechanism. Dogs accelerate the tongue upward (up to 4 g) to create a larger water column while drinking, whereas cats use a tongue motion with relatively small acceleration. We found that, in order to maximize the water intake per lap, both cats and dogs close the jaw at the column beak-up time governed by either unsteady or steady inertia. In the context of animal drinking, I will also talk about how bats drink water on the wing from a mechanics point-of-view, and illustrate an on-going design work to develop a bat-inspired vehicle to monitor the water quality along rivers or lakes. Second, we studied how birds with long slender necks plunge-dive and survive from the impact. Physical experiments of an elastic beam as a model for the neck attached to a skull-like cone revealed the limits for the stability of the neck during plunge-dive. We found that the small angle of the bird’s beak and the strong muscles in the neck predominantly reduce the likelihood of injury during high-speed plunge-dive. As a bio-inspired engineering, we design a bird-inspired projectile to explore underwater without propulsive mechanisms