This Major Research Instrumentation (MRI) provides funding to develop a multi-camera synthetic aperture technique for measuring high-speed, unsteady, 3-D velocity flow fields. The quantitative fluids imaging research group at Brigham Young University (BYU) is a combination of three laboratories and three PIs focused on experimental fluid dynamics as it relates to a myriad of multidisciplinary areas. The laboratory researchers embrace a philosophy of welcoming participation from other researchers within the broader university community on and off campus. The combined facilities support externally funded research projects, as well as both undergraduate and graduate hands-on instructional laboratories. The laboratories work together on research projects and share resources in an effort to encourage collaboration and camaraderie within the community. The toolset is focused on visualizing and quantifying fluid phenomena where an understanding of their behavior is crucial to understanding their basic physics. The phenomena include, but are not limited to, human respiratory airway flow patterns, insect flight aerodynamics, water-exit-entry of objects, multiphase flows, hydrophobic surface interaction, and thrombosis growth in blood flow. Thus far these systems have able to be studied using single-camera 2D PIV systems, hot-wire anemometry, or inferences from high-speed imaging. However, the group lacks a 3D flow visualization system and the ability to resolve flow fields in time. A novel new technique designed by the PI, in collaboration with MIT, uses several high-speed cameras to extract velocities from complex fluid flows. Velocities in the flow are quantitatively measured in three dimensions by using several viewpoints from multiple cameras. The planned system at BYU consists of ten high-speed cameras synchronized with a high-speed laser to capture transient volumetric flow field image data. Through a recombination of the 2D mages in the digital realm a 3D volume can be constructed for each time instant, thus providing time-resolved information in volumes as deep (Z) as the field of view (X-Y), with the tertiary advantage of being able to see around partial occluders, allowing us to analyze densely seeded flow volumes. This technique has the potential to become the standard for determining velocities of fluid flows in the coming years. The system overcomes some of the current 3D PIV disadvantages such as limited range and resolution and low particle seeding densities. For roughly the same cost as an off-the-shelf high-speed tomographic PIV system, larger out-of-plane dimensions and larger seeding densities, can be achieved while developing a new state-of-the-art system/technology that helps educate and inspire a new generation of students.
The research performed by the fluids imaging group is multidisciplinary and reaches across college, department, and university boundaries to support faculty, staff, and students from the Departments of Chemical, Mechanical and Civil Engineering as well as Physics, Chemistry, Biology and Mathematics. The instrumentation development will broaden the impact of the individual research projects by allowing the pursuit of a deeper understanding of the physical phenomena being studied. The technique will also improve understanding of future projects as the technique is disseminated among the scientific and engineering communities through a dedicated website, publication, and outreach activities. The development of the 3D Synthetic Aperture system will also benefit other aspects of science and engineering on and off the BYU campus, particularly undergraduate student education and experience. Many of the developers and users of the system will be undergraduates doing undergraduate research. Helping to develop a tool like this one will enable undergraduates to receive educational opportunities normally reserved for more advanced degree seekers. BYU is unique in this regard and a large institutional emphasis on undergraduate research exists. Over 75 percent of the graduates of the Mechanical Engineering program pursue advanced degrees, and experiences using the proposed system will provide excellent training for future impact in graduate level research and future careers. At BYU the best mentoring model combines faculty, graduate students, and undergraduates in synergistic research teams. The equipment will also be integrated into two course laboratories to extend the curriculum into high-speed, 3D methods and real world applications, while emphasizing the benefit of using multidisciplinary approaches to study difficult science and engineering problems. Finally, the developed system will be a high-profile system with far reaching multidisciplinary applications that will be leveraged to attract and recruit underrepresented students to STEM fields through outreach activities on campus.
