Hanging by a thread: how to fly at very low Reynolds numbers

Large (macro) bodies, such as whales and bumblebees, move about using thin membranes (fins and wings etc.). Extremely small (micro) bodies, such as spermatozoa, use slender filaments for movement. At the macroscale, locomotion is achieved by imparting momentum to the surrounding fluid. At the microscale, such a strategy would be foiled by large viscous drag forces; hence, locomotion is achieved by exploiting drag forces. 

At some lengthscale, there is a shift from using thin membranes to using filaments to move. In this talk, we will explore the hydrodynamic basis of locomotion in this "mesoscale" realm, with the common dandelion fruit as our tour guide.