Unsteady surface pressure measurements of propeller-wing interaction with a MEMS-embedded sleeve

• An innovative MEMS-based flexible sleeve is introduced for measuring unsteady surface pressure with minimal installation effort. • The sensor-embedded sleeve is experimentally validated against conventional unsteady pressure measurement techniques. • Unsteady aerodynamic interactions between a propeller slipstream and a NACA 633018 wing are characterized experimentally. • Microphone data capture propeller tip vortex traces and slipstream deformation over the wing surface. • The intermittency of the turbulent pressure fluctuations on the wing owing to the interaction with the propeller slipstream is analysed. This work investigates the unsteady aerodynamic interaction that arises from the impingement of a propeller slipstream on a wing. To this end, an innovative measuring device for unsteady pressure is deployed, comprising a flexible printed circuit board sleeve embedded with MEMS pressure sensors and microphones. The device performance is validated against conventional measurement techniques. The wing is a benchmarked NACA 63 3 018 airfoil-based model, and the propeller is the TUD-XPROP-S. In addition to pressure measurements, oil flow visualizations are performed to elucidate the flow pattern on the wing when the propeller operates at advance ratios of 0.8 and 1.8, and nominal blade pitch angles of 30° and 45°. The measurements reveal the formation of a laminar separation bubble on the portion of the wing not washed by the propeller slipstream. The flow is seen to remain attached on the advancing blade side, at least for the tested angles of attack. The microphone measurements capture the trace of the propeller’s tip vortices over the wing and the deformation of the slipstream over the wing. This work serves a dual purpose. Firstly, presenting an innovative measuring device for unsteady pressure, as the sensor-embedded sleeve requires minimal installation efforts and allows for a comprehensive measurement of the unsteady surface pressure field. Secondly, discussing the complex spatio temporal interaction that is formed from the impingement of a propeller slipstream onto a wing.