April 27th (Monday) Jun Zhang (Applied Math Laboratory, Courant Institute and Department of Physics, NYU)
Title: Ratcheting fluids: from reciprocal motion to unidirectional transportation
Abstract:
We will discuss two recent laboratory experiments that use reciprocal motion as the only means of energy input and examine the outcome as solid structures interact with the surrounding fluids. In the first experiment, we study the unidirectional flapping flight of a symmetric wing, resulted from a symmetry breaking bifurcation. We also study the effect of passive pitching (rotation) of a flat wing in response to fluid forces. In the second experiment, we discuss a new type of pump that effectively transports fluid using vibrational motion imposed onto shaped boundaries with anisotropy. Under reciprocal motion, fluid is transported unidirectionally.