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 63₃018 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.

We present an experimental set-up to perform time-resolved convective heat transfer measurements in a turbulent channel flow with air as the working fluid. We employ a heated thin foil coupled with high-speed infrared thermography. The measurement technique is challenged by the thermal inertia of the foil, the high frequency of turbulent fluctuations, and the measurement noise of the infrared camera. We discuss in detail the advantages and drawbacks of all the design choices that were made, thereby providing a successful implementation strategy to obtain high-quality data. This experimental approach could be valuable for studies employing wall-based measurements of turbulence, such as flow control applications in wall-bounded turbulence.