Print Email Facebook Twitter Experimental and numerical investigation into the drag performance of dimpled surfaces in a turbulent boundary layer Title Experimental and numerical investigation into the drag performance of dimpled surfaces in a turbulent boundary layer Author van Campenhout, O.W.G. (TU Delft Aerodynamics; Dimple Aerospace B.V.) van Nesselrooij, M. (TU Delft Aerodynamics; Dimple Aerospace B.V.) Lin, Y. (TU Delft Aerodynamics) Casacuberta Puig, J. (TU Delft Aerodynamics) van Oudheusden, B.W. (TU Delft Aerodynamics) Hickel, S. (TU Delft Aerodynamics) Date 2023 Abstract Although several previous studies have reported a potential drag-reducing effect of dimpled surfaces in turbulent boundary layers, there is a lack of replicability across experiments performed by different research groups. To contribute to the dialogue, we scrutinize one of the most studied dimple geometries reported in the literature, which has a dimple diameter of 20 mm and a depth of 0.5 mm. There is no general consensus in literature on the drag-reduction performance of this particular dimple geometry, with some studies suggesting a drag reduction, while others report a drag increase. The present combined experimental and numerical study comprises two sets of wind tunnel experiments and a well-resolved large-eddy simulation. The wind tunnel experiments and the large-eddy simulation both depict a total drag increase of around 1%–2% compared to the flat reference case. This finding agrees with a recent study by Spalart et al. (2019). Furthermore, the present wind tunnel experiments have shed light on a plausible reason behind the discrepancy between the study by Spalart et al. (2019) and earlier results from van Nesselrooij et al. (2016). Lastly, the large-eddy simulation results reveal that the pressure drag is the main contributor to the increase in the total drag of the dimpled surface. We believe that these results will contribute to a new consensus on the drag performance of this dimple geometry. Subject Dimpled surfaceDrag reductionLarge-eddy simulationTurbulent boundary layerWind tunnel experiment To reference this document use: http://resolver.tudelft.nl/uuid:55fc7798-8be5-44b1-82cb-38fd07c9addd DOI https://doi.org/10.1016/j.ijheatfluidflow.2023.109110 ISSN 0142-727X Source International Journal of Heat and Fluid Flow, 100 Part of collection Institutional Repository Document type journal article Rights © 2023 O.W.G. van Campenhout, M. van Nesselrooij, Y. Lin, J. Casacuberta Puig, B.W. van Oudheusden, S. Hickel Files PDF 1_s2.0_S0142727X23000097_main.pdf 2.83 MB Close viewer /islandora/object/uuid:55fc7798-8be5-44b1-82cb-38fd07c9addd/datastream/OBJ/view