Lau, Nolan CK;
Klettner, Christian A;
(2025)
Vorticity generation, transport, and annihilation under steep solitary waves.
Physics of Fluids
, 37
(9)
, Article 097173. 10.1063/5.0287404.
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Abstract
Solitary waves are often modeled as irrotational fluids, which fail to consider the bottom and free-surface boundary layers. In this work, we consider the behavior of the less researched, free-surface boundary layer using a novel finite volume numerical method composed of two steps. The first stage calculates the irrotational velocity field, then the second stage resolves the boundary layer. The method presented is considerably more computationally efficient than previous approaches, such as direct numerical simulation of the Navier–Stokes equations. The results indicate that the free-surface boundary layer is thin and weak, featuring a region of positive vorticity enclosed by negative vorticity. The presence of opposite-signed vorticity also leads to annihilation where opposite-signed vorticity of equal magnitude cross-diffuses and cancels each other out. A parameter study of varying wave steepness of 0.2, 0.5, and 0.75 and Reynolds numbers of 1000, 5000, and 10 000 was conducted. Like rigid boundary layers, the free-surface boundary layer becomes thinner with an increasing Reynolds number. The velocity field and geometry associated with the specific wave steepness affect the boundary layer structure. While the overall effect of the free-surface boundary layer is small compared to the irrotational flow, its effects can be significant in certain circumstances and certain aspects, such as particle drift.
| Type: | Article |
|---|---|
| Title: | Vorticity generation, transport, and annihilation under steep solitary waves |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/5.0287404 |
| Publisher version: | https://doi.org/10.1063/5.0287404 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Science & Technology, Technology, Physical Sciences, Mechanics, Physics, Fluids & Plasmas, Physics, NUMERICAL-SIMULATION, BOUNDARY-LAYER, STOKES DRIFT, SURFACE, WATER, LAMINAR, CURRENTS, SERIES, FLOW |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10215447 |
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