MRI: Development of Long Distance Microscope Velocimetry System for Bridging Macro and Microscales

Proposal No. CTS-0320327

Principal Investigator: E. Longmire, University of Minnesota

This grant is for a unique instrumentation system to be developed for simultaneous characterization of microscopic and macroscopic flow evolution. The system will first be used to examine two flows, which by their nature are characterized by a wide range of scales: turbulent and interfacial flows. The system, which will be developed in collaboration with LaVision, Inc, will include the required illumination and imaging optics to apply the Stereo-Particle Imaging velocimetry technique simultaneously at two magnifications and at repetition rates high enough to characterize the flow evolution. In addition, custom calibration targets and software as well as custom analysis software will be developed in order to achieve results of high accuracy in the overlapping smaller and larger fields of view. In the smaller field of view, the system will be able to resolve velocity vectors in areas of (100 square micrometer) or less, while the larger field of view may cover an area of (10 square cm) or more. These aspects will allow for observation and characterization of the evolving microscopic scales in the context of the macroscopic behavior. After the system is developed, it will be employed immediately in studies of turbulent boundary layers and drop coalescence.

The instrumentation described will provide revolutionary advances in the understanding of both coalescence at interfaces and the interaction of eddies in turbulent boundary layers. Also, the availability this system will allow for novel and groundbreaking research in additional areas of fluid dynamics including, for example, laminar/turbulent transition, control of macroscopic flows with MEMS, liquid jet and drop break up, three-dimensional instabilities, and turbulent separated flows.

The proposed system, which could become a product supported by multiple vendors, is expected to be useful to researchers in many areas of fluid dynamics. At the University of Minnesota, several graduate students will be involved with the proposed system. One will design, develop, and integrate the system hardware and software, and others will use the system for the research projects described above. Also, undergraduate researchers and high school physics teachers, funded by REU and RET supplements, will perform and participate in short-term investigations during the summers. The teachers are expected to bring their experiences with cutting edge measurement techniques and engineering applications back to the classroom.