CAREER: High Resolution Particle Tracking in Granular and Turbulent Fluid Flows

Wesleyan University, Middletown CT

Investigators

Abstract

*******NON-TECHNICAL ABSTRACT******* This Faculty Early Career award supports a project to measure particle trajectories in turbulent fluids and granular flows. A novel system combining stereoscopic high speed imaging with real-time image processing will be developed to track the particles. This system has many similarities to the way the human visual system tracks objects, and it has potential for broad application. The studies are expected to help resolve key questions such as how turbulent trajectories depend on the method of creating the flow and how sediments are transported in turbulence. High-speed imaging will also be used to measure the rapid changes that occur in flowing grains. Granular materials can quickly transition between a fluid-like state with many collisions between particles and a stationary pile with no particle motion. The studies will guide the search for a better description of these transitions. These results would be of interest to industries such as agriculture and mining, where granular materials are widely used. Two educational and outreach initiatives will be pursued. Upper level undergraduate courses in quantum and classical mechanics, emphasizing the active engagement of students in learning through experimental activities, will be developed at Wesleyan University. Through a partnership with PIMMS (Project to Increase Mastery of Mathematics and Science), the faculty member will train elementary teachers in urban school districts in mastering the content of the physical science units they teach to their students. This project is co-funded by the Division of Materials Research (Condensed Matter Physics) and the Division of Chemical Transport Systems (Particulate and Multiphase Processes). ********TECHNICAL ABSTRACT***** This Faculty Early Career award supports a project to develop our dynamical understanding of turbulent and granular flows through high-resolution optical particle tracking measurements. The project will develop a novel imaging design that uses stereoscopic high-speed imaging and real-time image processing to acquire 3D trajectories of particles advected in turbulent fluid flow. These studies will help resolve key questions about the universality of turbulent trajectories and the motion of large and non-neutrally buoyant particles in turbulent flows. In granular flows, precision particle tracking will allow new measurements of time-dependent statistical fields. Measurements in a vibrofluidized quasi-2D granular gas undergoing gravitational collapse will provide critical tests of how hydrodynamic approximations begin to fail. In addition two educational and outreach initiatives will be pursued. Upper level undergraduate courses in quantum and classical mechanics, emphasizing the active engagement of students in learning through experimental activities, will be developed at Wesleyan University. Through a partnership with PIMMS (Project to Increase Mastery of Mathematics and Science), the PI will train elementary teachers in urban school districts in mastering the content of the physical science units they teach to their students. This project is co-funded by the Division of Materials Research (Condensed Matter Physics) and the Division of Chemical Transport Systems (Particulate and Multiphase Processes).