Bio- & Nature-inspired

 

We explore bio- and nature-inspired problems which are multidisciplinary fluid dynamics problems, e.g. mimicking nature systems to clean environments, human and plant diseases, and mimicking natural structures.

 

 

 
We experimentally study a gravity-driven liquid flow on a flexible beam. The elastic material bends due to the weight of the liquid. The relationship between hydrodynamics and elasticity is investigated by varying an applied flow rate, the bending stiffness of the beam, and the beam length. Surface tension effects are negligible for these experiments. We compare our results with a model that predicts the beam deformation in terms of two dimensionless parameters, one representing a dimensionless beam length and the other representing a dimensionless beam stiffness. The results span both small deformations as well as large deformations of the cantilever.

Related publication:
1) P.D. Howell, J. Robinson, and H.A. Stone "Gravity-driven thin-film flow on a.flexible substrate," J. Fluid Mech. 732, 190-213 (2013)
2) P.D. Howell*, H. Kim*, M. Popov, H.A. Stone, "Rivulet flow along a flexible substrate," J. Fluid Mech. 796, 285 (2016) *Equivalent 1st co-author.
 
The small water droplets (the diameter is typically around 1-10 μm) falls down to the ground and the jet was applied to the horizontal direction (right to left). The dispersion pattern of droplets is taken by high-speed camera, Photron SA-X @ 50,000 fps.
 
Some butterfly has a beautiful flap color that is created by a well-ordered nano structure. The reflected color depends on a typical structure size and the inter distance between particles. It is so-called "photonic crystal structures". This structure can be used as counterfeit technologies. The color changes depending on the viewing direction, which is iridescence. Inspired by nature materials, we explore the nano materials' packing mechanism and furthermore we are interested in controlling packing structures by using physico-chemical hydrodynamic effects.