Wall Shear Stress and Flow Direction Thermal MEMS Sensor for Separation Detection and Flow Control Applications

Abstract

We report a study on a wall shear stress and flow direction hot-wire based sensor operating in anemometric mode. The sensor is designed to achieve fast response time and high sensitivity. The sensor structure consists in free hot wires over insulator bridges and exhibits sensitivity to wall shear stress variations and to flow direction. The sensor can be wall-mounted for applications such as flow control or turbulence analysis. Finite elements simulations have been made to demonstrate a fast thermal response time to fluid velocity of about 300 μs in constant current operating mode and a sensitivity to wall shear-stress fluctuations. Electrical characterizations and wind tunnel experiments were performed to analyze the sensor response to respectively heat power and flow velocity.