This project will advance a novel, biologically inspired method for the manipulation of solid particles suspended in fluids on a microscopic scale through complementary theoretical, computational, and experimental research. A comprehensive mathematical framework will be developed for describing the control of fluid flows at low Reynolds number through localized cyclic boundary deformations using concepts from differential geometry and dynamical systems theory. A high-fidelity numerical approach will be developed for simulating such problems using a viscous vortex particle method. A pair of experimental platforms on contrasting physical scales will be constructed, each comprising a system of reconfigurable resonant probes mimicking cilia observed in nature, and extensive data will be collected to calibrate both theoretical and computational models. Algorithmic methods for separating and sorting particles, and for tailoring the spatial trajectories of individual particles, will be devised and demonstrated experimentally.
The project focuses on developing and demonstrating a novel technique for separating and manipulating fragile microscopic objects immersed in fluids, which has a growing list of applications ranging from the mechanical testing of macromolecules like DNA to the assisted fertilization of human ova with immotile sperm to the sustained excitation of fluid-borne abrasive particles for the precision machining of brittle surfaces. Models will be developed to predict the trajectories of particles in fluids containing multiple vortex fields. These vortex fields will be produced experimentally using oscillating fibers. A pair of experimental platforms with millimeter and micrometer (1/1000 of a millimeter) physical scales will be constructed. For each platform, a system of reconfigurable resonant probes will be used to generate steady vortex fields in particle-bearing fluids. The smallest probes will mimic the microscopic oscillating cilia observed in nature. Data will be collected to validate the theoretical and computational predictive models. This project will not only engender integrated advancements in applied mathematics, computational science, and engineering, but will also shed light on the physics underlying a physiological design present in protozoa and humans alike. The micromanipulation method to be developed represents an improvement over alternative technologies in simplicity, portability, and cost. The PIs' plan for developing this method incorporates a multi-institutional collaboration involving the directed mentoring of at least one postdoctoral researcher, at least two PhD students, and a number of undergraduates (with a deliberate eye toward promoting diversity), the curricular expansion of two cross-disciplinary graduate courses and two undergraduate courses at the PIs' universities, and outreach to biology students at a third university and to high school students in an ethnically diverse area.
