Towards Drag Reduction on a Morphing Wing by Transition Detection and Delay using Kulite Sensors and Smart Material Actuators (original) (raw)

In this paper, wind tunnel experiment was performed for boundary layer transition control on a morphing wing. Surface pressure fluctuations were measured using Kulite transducers at high sampling rate. A controller, linking the Kulites signals fluctuation to the smart material actuators, is incorporated to the control system, where the signals are analyzed and the transition location is detected. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 × 9 ft 2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross section due to a flexible skin installed on the upper surface of the wing, was instrumented with sixteen Kulite transducers. The Mach number was varied from 0.2 to 0.3 and the angle of attack between-1 o and 2 o. Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions using the XFoil computational fluid dynamics code. The unsteady pressure signals were analyzed through FFT spectral decomposition for detecting the Tollmien-Schlichting waves frequencies that trigger transition. In addition, infra red measurements were performed to asses the performance of the Kulite transducers in detecting the transition location and serve as an additional validation of the XFoil code in predicting the transition location .