Projects

• Topological defects and self-organization in sheets We investigate how an elastic sheet buckles and folds under the application of external stresses. Singularities in the form of ridges and vertices can be readily observed to be organized in ordered and disordered networks. Optical and micro x-ray tomography techniques enable us to extract the curvature of the resulting surfaces and thus the spatial distribution of the bending and stretching energies.
• Erosion We investigate the physics of erosion starting with the conditions which give rise to onset of particle motion on a rough bed and in a granular bed due to fluid flow from the laminar to the turbulent regime. We can examine the flow near the interface and the particles inside the bed by using index matching and fluorescent imaging. Understanding this system is important to a range of problems such as beach erosion, turbidity currents, sand dune motion, proppant deposition in hydraulic fracturing, drug delivery via inhalation, and biofilms.
• Packing beyond Kepler We are examining how athermal objects ranging from cohesive to hard spheres and elastic solids, sheets, and filaments pack in two and three dimensions and curved interfaces. Of interest is the random packing of rods, polyhedrons, and other novel shapes, and their strength. Dynamical self-organization beyond entropy maximization is of further particular interest.
• Intruder dynamics in hydrogels We are interested in how particles sediment in complex fluids including viscoplastic materials. In contrast with Newtonian fluids, the rheology of the material is also not as well known. Hydrogels are a model viscoplastic material that can be used to understand sedimentation and locomotion in yield stress materials.
• Instabilities of filaments in viscous medium The interaction of elastic objects with fluids is a fascinating but difficult problem. To understand such systems, we are examining a range of models in the viscous and inertial regimes motivated by soft robotics and biological systems.