Print Email Facebook Twitter Alleviation of Propeller-slipstream-induced unsteady pylon loading by a flow-permeable leading edge Title Alleviation of Propeller-slipstream-induced unsteady pylon loading by a flow-permeable leading edge Author Sinnige, T. (TU Delft Flight Performance and Propulsion) della Corte, B. (TU Delft Flight Performance and Propulsion) de Vries, R. (TU Delft Flight Performance and Propulsion) Avallone, F. (TU Delft Wind Energy) Merino Martinez, R. (TU Delft Aircraft Noise and Climate Effects) Ragni, D. (TU Delft Wind Energy) Eitelberg, G. (TU Delft Flight Performance and Propulsion) Veldhuis, L.L.M. (TU Delft Flight Performance and Propulsion) Date 2019 Abstract The impingement of a propeller slipstream on a downstream surface causes unsteady loading, which may lead to vibrations responsible for structure-borne noise. A low-speed wind-tunnel experiment was performed to quantify the potential of a flow-permeable leading edge to alleviate the slipstream-induced unsteady loading. For this purpose, a tractor propeller was installed at the tip of a pylon featuring a replaceable leading-edge insert in the region of slipstream impingement. Tests were carried out with four flow-permeable inserts, with different hole diameters and cavity depths, and a baseline solid insert. Particle-image-velocimetry measurements showed that the flow through the permeable surface caused an increase in boundary-layer thickness on the pylon's suction side. This led to a local drag increase and reduced lift, especially for angles of attack above 6 deg. Furthermore, it amplified the viscous interaction with the propeller tip-vortex cores, reducing the velocity fluctuations near the pylon surface by up to 35%. Consequently, lower tonal noise emissions from the pylon were measured in the far field. This suggests that the desired reduction in surface pressure fluctuations was achieved by application of the flow-permeable leading edge. To reference this document use: http://resolver.tudelft.nl/uuid:f2e4e6c3-3bb7-4c34-9e0c-327897a4958e DOI https://doi.org/10.2514/1.C035250 ISSN 0021-8669 Source Journal of Aircraft: devoted to aeronautical science and technology, 56 (3), 1214-1230 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 © 2019 T. Sinnige, B. della Corte, R. de Vries, F. Avallone, R. Merino Martinez, D. Ragni, G. Eitelberg, L.L.M. Veldhuis Files PDF 1.c035250.pdf 2.51 MB Close viewer /islandora/object/uuid:f2e4e6c3-3bb7-4c34-9e0c-327897a4958e/datastream/OBJ/view