Print Email Facebook Twitter Experimental Investigation of Over-the-Wing Propeller–Boundary-Layer Interaction Title Experimental Investigation of Over-the-Wing Propeller–Boundary-Layer Interaction Author de Vries, R. (TU Delft Flight Performance and Propulsion) van Arnhem, N. (TU Delft Flight Performance and Propulsion) Avallone, F. (TU Delft Wind Energy) Ragni, D. (TU Delft Wind Energy) Vos, Roelof (TU Delft Flight Performance and Propulsion) Eitelberg, G. (TU Delft Flight Performance and Propulsion) Veldhuis, L.L.M. (TU Delft Flight Performance and Propulsion) Date 2021 Abstract This experimental study focuses on the aerodynamic interaction between an over-the-wing (OTW) propeller and a wing boundary layer. An OTW propeller is positioned above the hinge line of a wing with a trailing-edge flap. Measurements are carried out with and without axial pressure gradients by deflecting the flap and by extending the flat upper surface of the wing in the streamwise direction, respectively. Surface-pressure taps, microphones, and particle image velocimetry are combined to quantify both the time-averaged and unsteady interaction effects. Results show that the propeller generates an adverse pressure gradient on the wing surface that scales linearly with thrust and decreases with increasing blade-tip clearance. The pressure gradient is partially caused by slipstream contraction, which decelerates the flow near the wall. Additionally, the surface-pressure fluctuations generated beneath the propeller blades and slipstream are stronger than the time-averaged pressure increase due to flow deceleration. Consequently, the propeller triggers flow separation over the hinge line when the flap is deflected. A parametric study of different propeller locations indicates that increasing the tip clearance is not an effective way to mitigate flow separation. However, displacing the propeller half a radius upstream of the hinge line creates a Coandă effect, which allows the flow to remain attached. To reference this document use: http://resolver.tudelft.nl/uuid:868f85bf-3030-4641-bcb0-f5410b5a4128 DOI https://doi.org/10.2514/1.J059770 Embargo date 2021-10-01 ISSN 0001-1452 Source AIAA Journal: devoted to aerospace research and development, 59 (6), 2169-2182 Bibliographical note Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of collection Institutional Repository Document type journal article Rights © 2021 R. de Vries, N. van Arnhem, F. Avallone, D. Ragni, Roelof Vos, G. Eitelberg, L.L.M. Veldhuis Files PDF 1.J059770.pdf 2.84 MB Close viewer /islandora/object/uuid:868f85bf-3030-4641-bcb0-f5410b5a4128/datastream/OBJ/view