This grant is to develop a novel wall shear stress sensor based on a resonant device. This resonant device is sensitive to shear stress through changes in the resonance caused by the time dependent shear force acting on the sensor. This device will have high sensitivity to shear stress, low sensitivity to other forces, and high bandwidth. Based upon preliminary work the concept shows promise, but further work is needed to demonstrate the viability of the sensor under a range of conditions. The intellectual merit is encompassed in three specific aims for this work: investigate scaling issues by developing various scale MEMS sensors; continue model development by validating and applying the two-dimensional model already developed and extending simulations to three dimensions; and characterization of the sensors in an existing two-dimensional channel and in a new variable pressure gradient wind tunnel. The results of the work proposed here on this new and largely untested sensor class will establish its viability and justify its further development. In the process, the sensor design will be refined, and experience working with such sensors will be gained. The broader impacts of this work will include advancing discovery while promoting teaching and learning, broadening the participation of underrepresented groups, and broad dissemination of results. With further development, the wall shear stress sensor is likely to have a profound impact on many areas, including the aeronautics, medical, and industrial fields, since the information provided by dynamic wall shear stress sensors would be extremely useful. The breadth of the impact is obvious when one considers the widespread use of pressure transducers and that, in many cases, shear stress is a better measurement for process control. Aside from the potential high impact of the sensor on many applications, ongoing work is contributing to training undergraduates and graduate students in the highly interdisciplinary field of sensor system development.
