ABSTRACT
This chapter overviews some advances in unsteady biofluid dynamics in terms of leading-edge vortices, passive mechanisms in flexible wings and hinges and flapping flight in unsteady environments, as well as undulatory swimming, flapping-fin hydrodynamics, body-fin interactions, C-start and maneuvering, swimming in turbulence and collective swimming. It highlights the state of the art in biomimetics of flapping-wing micro-air vehicles (MAVs) and swimming robotics MAVs. The aerial environment of flying animals is complex and variable, as it incorporates unsteady flows of diverse origins, instability of the inflected mean flow velocity profiles in vegetation canopy layers and small-scale turbulence produced in the wakes of the foliage. The impact of wind conditions on animal flight has studied in relation to migration and foraging using field observations. The diamond formation optimization seems quite conditional. To realize the diamond formation optimization, fish in school need to produce single-row vortex rings to ensure that vortices are in uniform rotational direction on one flank of the vortex street.
