Print Email Facebook Twitter An experimental investigation into the flow mechanics of dimpled surfaces in turbulent boundary layers Title An experimental investigation into the flow mechanics of dimpled surfaces in turbulent boundary layers Author van Campenhout, O.W.G. (TU Delft Aerodynamics) van Nesselrooij, M. (TU Delft Aerodynamics) Veldhuis, L.L.M. (TU Delft Flight Performance and Propulsion) van Oudheusden, B.W. (TU Delft Aerodynamics) Schrijer, F.F.J. (TU Delft Aerodynamics) Date 2018 Abstract Although various experimental studies have confirmed the potential drag reducing effect of dimpled surfaces in a turbulent boundary layer, the working mechanism remains largely unresolved. An experimental investigation has been performed with the objective to strengthen the understanding of this aerodynamic surface and its interaction with the turbulent boundary layer. Direct force measurements were combined with Particle Image Velocimetry (PIV) and Particle Image Surface Flow Visualization (PISFV). The direct force measurements reveal that the drag reduction is highly sensitive to flow conditions: a finding with significant implications for further research as well as for potential applications. Furthermore, the PIV and PISFV measurements reveal a spanwise oscillation of the flow near the surface due to the interaction of individual dimple flow topologies, which are of the converger-diffuser type. The measurement of this oscillation provides evidence for a novel drag reduction theory: the interaction between dimples causes alternating spanwise excitations of the near-wall flow which interacts with the turbulent coherent structures which leads to a reduction of the turbulent drag. To reference this document use: http://resolver.tudelft.nl/uuid:bb3e62c8-814b-4875-8c5a-693e8840004b DOI https://doi.org/10.2514/6.2018-2062 Publisher American Institute of Aeronautics and Astronautics Inc. (AIAA) Embargo date 2021-12-08 ISBN 9781624105241 Source AIAA Aerospace Sciences Meeting (210059) Event AIAA Aerospace Sciences Meeting, 2018, 2018-01-08 → 2018-01-12, Kissimmee, United States 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 conference paper Rights © 2018 O.W.G. van Campenhout, M. van Nesselrooij, L.L.M. Veldhuis, B.W. van Oudheusden, F.F.J. Schrijer Files PDF 6.2018_2062.pdf 3.13 MB Close viewer /islandora/object/uuid:bb3e62c8-814b-4875-8c5a-693e8840004b/datastream/OBJ/view