Development of a Sensor for Inflight Detection of Three-Dimensional Flow Separation on a Wing

Abstract

A real need exists for a sensor capable of detecting flow-field separation on an airplane wing during routine flight operations. A sensor of this type could lead to both improved flight safety and increased performance. It would also contribute to future separation control technologies. A new idea is presented for a sensor that is cost effective, easy to maintain, durable, and highly effective. The system, known as a Thermal Grid, works by using a grid of heaters and temperature sensors to trace out the streamlines closest to the surface. Specific singularities in these streamlines are excellent indicators of flow separation. This paper addresses many of the necessary principles that are necessary to making the Thermal Grid an operational device. An analytic design is presented that details the system requirements and potential performance, including heater/sensor spacing, heater power requirements, sensor time response and sensitivity needs and the effects of changes in flow conditions.