This award will make possible the purchase of a system of Particle Imaging Velocity (PIV), a universal research microscope, a rheometer and a few smaller equipments. With these instrumentations, the investigators will study a number of fluid problems that involve unsteady fluid flows interacting with mobile boundaries. In particular, it is planned to study the free flight of a rigid wing that is flapped at prescribed wave forms. The PIs will address questions related to the generation of thrust at early stages as the wing initiates a unidirectional flight. They will also study the effects of a flapping wing that is able to pitch during its flight, and compare its performance to a non-pitching wing, as well as the instability associated with flapping flags and the mechanism by which forced flags produce different types of wake structures. This experiment will address the question of the connections and differences between a flapping flag and a swimming fish. Moreover, it is well known that fluid pumping and animal locomotion share many common aspects, and can be studied using similar theoretical treatments. The planed study will investigate the transport of fluid using anisotropic geometry (ratchets) and the swimming of a model organism (C. elegans) in viscous fluids. The studies will be extended to complex fluids, since nonlinear responses take place in these systems even at low Reynolds numbers. The requested instrumentations will realize a fundamental improvement at the Applied Mathematics Laboratory (AML), which will allow the investigation of dynamical boundary problems in moving fluids with added precision and flexibility. The research projects will involve scientists at all levels, ranging from faculty members to motivated undergraduate and high-school students.
