Proposal Title: MRI: Development of a Micro-Optical Sheer Stress Sensor for Fluid Mechanic Research
Proposal Number: CTS-0619193-MRI
Principal Investigator: M. Volkan Otugen
Institution: Polytechnic University of New York
In this research, a novel micro-optical wall shear stress sensor will be developed for a number of fluid mechanics research projects at Polytechnic University. The micro-optical sensor is based on dielectric micro-beads that are excited by coupling light from an optical fiber. The technology exploits the morphology-dependent shifts in resonant frequencies that are commonly referred to as the whispering gallery modes (WGM). A minute change in the size, shape or optical constants of the micro-bead causes a shift in the resonant frequency (or the WGM). This shift can be related to the stress on the micro-bead. The sensor will provide direct, time-resolved, high-sensitivity, large bandwidth measurement of wall shear stress that is well resolved in space.
The proposed research will develop a new concept for micro-optical wall shear stress sensors that is based on the WGMs of dielectric resonators which exploits recent technological developments in the telecommunications field. The effort will demonstrate a micro-optical wall shear stress sensor concept that has superior resolution and dynamic range than the currently available sensors and that has applications for both water and gas flows. The optical phenomenon that will be used in this effort can be exploited for the development of a new class of micro-sensors that can be used for a wide range of fluid dynamic applications; any physical stimuli that can directly or indirectly change the size, shape or optical constants (thereby causing a shift in the WGM) can be detected with resolution that are beyond what can be realized by the existing mechanical sensors. Further, the concept can be easily extended to a system of distributed micro-sensors providing spatial data that is also time-resolved. Although it is presently proposed to apply this optical phenomenon to develop wall shear stress sensors for use in fluid mechanics research projects, many other applications are possible including high-resolution temperature sensors. With the growth of wide-band communications through optical fibers, the use of WGMs of miniature optical elements are rapidly becoming commonplace in the telecommunication industry where components that are several wavelengths of light in size are used. However, such components are seldom manipulated mechanically to develop new sensor technologies.
Although the primary area of application for the proposed sensor is fluid mechanics research, the proposed activity will have a much broader impact: the micro-optical wall shear sensor can have a significant impact on the modeling of pipeline networks, process control in manufacturing industries, and medical field uses. Further, the successful completion of this effort will lay the groundwork for the development of a much broader range of WGM-based sensors for temperature, pressure and species concentration. Therefore, with the development of rugged, reliable optical sensors of this kind, the long-term payoff are likely to be very significant. An interdisciplinary team of researchers will carry out the development activity. The development effort, along with the research projects, will have a direct impact on undergraduate and graduate education at Polytechnic University. These activities will form the basis of graduate student (PhD) dissertations and undergraduate student (Honors Program) theses. Further, through the Youth in Engineering and Science (YES) program at Polytechnic, a number of high-school students with diverse backgrounds from the New York metropolitan area will be trained during the summer months. Additionally, a number of undergraduate and graduate courses will directly benefit from the instrument development activity.
