"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."
A team of five faculty actively engaged in fluid dynamics research from the College of Engineering at the University of Alabama (UA) proposes to acquire a TSI V3V measurement system. The V3V system is unique, compared to planar two-dimensional and even stereoscopic particle image velocimetry (PIV) systems, because it is capable of measuring the instantaneous three-component velocity vector field within an entire fluid volume. The instrument uses a system of three cameras to track the three-dimensional coordinates of individual particles; the data are then interpolated onto a regularly spaced Cartesian grid. As a result, other three-dimensional flow properties (such as vorticity, local strain rates, and Reynolds stresses) are easily calculated from the measurements. The major advantage of the system is its ability to fully capture the velocity field spatio-temporally while only requiring limited optical access as compared to planar DPIV, thus allowing for greater insight into the flow physics for the proposed studies. UA would be the first university in the Southeast to purchase this state-of-the-art system and would become one of less than ten in the country to acquire one. The acquisition of the V3V will enable the faculty team, which has combined experience of 23 years using planar PIV systems, about 60 years with laser-based techniques, and over 80 years with optical measurement techniques, to form a new, active working group that focuses on optical diagnostic techniques in experimental fluids, aerodynamics, combustion and engines (eFACE Working Group). The V3V will provide the infrastructure cornerstone of the newly formed working collaboration.
The purpose of this MRI is to acquire a Volumetric Three-Component Velocimetry (V3V) measurement system capable of measuring all three components of the velocity vectors for unsteady flows in a three-dimensional volume. This system provides a complete description of the flowfield around objects which enables aerodynamicists to better understand the details of air/water flow around many engineering applications such as aircraft, helicopters, missiles, wind turbines, ground vehicles and marine vehicles. The V3V system also assists measuring the complex and three-dimensional flowfield around insects, birds and fish. The understanding of how natural fliers and swimmers establish fast and agile movements helps researchers apply the lessons learned from nature to design more efficient and capable vehicles, whether small aircrafts, road vehicles or ships. Five faculty members within the College of Engineering at The University of Alabama, who are actively involved in engineering fluid dynamics research, are using this state-of-the-art measurement system in their ongoing and future sponsored research projects. Additionally, postdoctoral associates, graduate students, and undergraduate students are actively involved in several research projects using the V3V system. Several stages of these research projects have already been carried out, with other stages currently underway and planned for the future. The results of our studies have been shared with the scientific community in the forms of conference presentations and proceedings, and journal publications. Studies concerned with flow separation are being carried out in a water tunnel. Since flow separation is a major hindrance to the performance of lifting bodies such as aircraft wings and wind turbine blades, several projects are being conducted to learn more details of this flow phenomenon using a more global and detailed view provided by the V3V system. The figure attached shows vortex structures occurring in a separated flow measured using V3V with the coloring indicating the distance away from the surface. We are also able to combine our understanding gained from these experiments with findings from nature to delay or prevent the flow separation. This is accomplished by investigating the effects of the flexible shark scales found on fast-swimming sharks for controlling flow separation. This study is being carried out as a collaborative investigation between engineers at the University of Alabama and biologists in Florida. The V3V system is also being used for flow measurements around a new three-dimensional wing design inspired by bat wings. These experiments are directed towards designing efficient wings for Micro Air Vehicles (MAVs). The flowfield measurements are combined with lift and drag measurements to correlate the aerodynamics benefits in terms of increased lift and decreased drag with certain flow features. Researchers at The University of Alabama are also collaborating with developers of the V3V system to improve this measurement technique and expand its capabilities to more-challenging flow problems that the scientific community finds useful. The data collected from this system are are also being shared with researchers from other institutions who conduct research using computational fluid dynamics (CFD) to validate their findings. The V3V system is used for educational purposes in addition to the mentioned research endeavors. For example, senior students who are enrolled in experimental aerodynamics laboratory courses are provided with the opportunity to learn about the system and use it for their design projects and for future participation in research as graduate students. Also, undergraduate students who are admitted to the Honors program at The University of Alabama are encouraged to participate in experimental fluid dynamics research using this system. Undergraduate engineering students from other institutions across the nation can use this system through their admission to the site for Research Experience for Undergraduates (REU) at The University of Alabama. This site is funded by the National Science Foundation (NSF) to encourage undergraduate engineering students to participate in fluid dynamics research.
