Granular Media and Suspensions (Dr. Joshua A. Dijksman)

“Of all the secrets that Nature has concealed by her method of deadening curiosity by leaving them exposed, in this her method has been the most successful”

Osborne Reynolds, 1899

The famous Osborne Reynolds (yes, from the Reynolds number) wrote the lines above with the slipperiness of ice in mind. Yet he might have been discussing many other things: everyday phenomena are rich in interesting and novel physics. Be it the way liquid droplets attach to a soft substrate, the way potatoes become crunchy when you fry them, or the way sand flows: all are just examples of the fascinating physics in materials of everyday life. They often feature unresolved puzzles (the slipperiness of ice still being one of them) and regularly open doors to unexplored rooms of physics. Indeed, the richness of observations is often due to the interplay of various basic physical mechanisms at “miniature” length scales, such as viscous effects, friction, surface tension, adhesion and electrostatic interactions.

The Granular Media and Suspensions group of Joshua Dijksman digs deeper into these issues. The main focus is the mechanical behavior of sand, more technically granular media, including the flow behavior of suspensions [1, 2, 3], the role of fluctuations in flowing granular media [4] and the compressibility static packings of soft particles [5, 6]. We employ an array of experimental techniques, such as rheology, three-dimensional imaging [7], photo elasticity, 3D printing and Matlab-based image analysis, to probe the extremely diverse behavior of these fascinating material.