A Flat-Packaged Optical Shear Stress Sensor Using Moiré Transduction for Harsh Environments

As the field of hypersonic vehicle design develops, having shear stress data can aid in the minimization of 
drag source effects and verify results from computational fluid dynamics simulations. Transducer size, 
placement, and narrow bandwidth currently limit accurate shear stress measurements due to the small 
length and time scales seen in turbulent fluid motion and the issue of flow disruption. Shock wave and 
boundary layer effects also produce large thermal loads in hypersonic flows. The proposed research plan 
includes the design, optimization, fabrication, and testing of a flat-packed, sapphire MEMS optical shear 
stress sensor. The material selection will ensure sensor functionality up to 1000°C, while microfabrication 
techniques will extend the bandwidth to capture sub-mm wavelength phenomena. After an optimized 
sensor design is selected and produced, it will be packaged and calibrated in static and dynamic 
environments, making it viable for real-world hypersonic applications.