Print Email Facebook Twitter Effect of the Stokes boundary layer on the dynamics of particle pairs in an oscillatory flow Title Effect of the Stokes boundary layer on the dynamics of particle pairs in an oscillatory flow Author Van Overveld, T. J.J.M. (Eindhoven University of Technology) Breugem, W.P. (TU Delft Multi Phase Systems) Clercx, Herman J.H. (Eindhoven University of Technology) Duran-Matute, M. (Eindhoven University of Technology) Date 2022 Abstract The alignment of a pair of spherical particles perpendicular to a horizontally oscillating flow is attributed to a non-zero residual flow, known as steady streaming. This phenomenon is the basis of complex patterns in denser systems, such as particle chains and the initial stages of rolling-grain ripples. Previous studies on such self-organization processes used two distinct systems: an oscillating box filled with viscous fluid and an oscillating channel flow, where the fluid oscillates relative to the bottom boundary. In this paper, we show that particle pair dynamics in these two systems are fundamentally different, due to the presence of a Stokes boundary layer above the bottom in the oscillating channel flow. The results are obtained from direct numerical simulations in which the dynamics of a pair of particles are simulated using an immersed boundary method. The oscillating box and the oscillating channel flow are only equivalent in a limited region of the parameter space, where both the normalized Stokes boundary layer thickness and the normalized relative particle excursion length are small. Overall, the particle dynamics in the oscillating channel flow, compared to the oscillating box, are governed by an additional dimensionless parameter, that is, the particle–fluid density ratio. To reference this document use: http://resolver.tudelft.nl/uuid:4d4aa9eb-708c-4706-8669-37c10e90ea27 DOI https://doi.org/10.1063/5.0115487 Embargo date 2023-07-01 ISSN 1070-6631 Source Physics of Fluids, 34 (11) 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 © 2022 T. J.J.M. Van Overveld, W.P. Breugem, Herman J.H. Clercx, M. Duran-Matute Files PDF 5.0115487.pdf 2.82 MB Close viewer /islandora/object/uuid:4d4aa9eb-708c-4706-8669-37c10e90ea27/datastream/OBJ/view