Backwards wave breaking by flow separation vortices under solitary waves. (November 2022)

• Record Type: Journal Article
• Authors: Cáceres-Euse, Alejandro; Orfila, Alejandro; Hernández-Carrasco, Ismael; Wyssmann, Micah A.; Osorio, Andrés F.; Toro-Botero, Francisco
• Is Part Of: Journal of fluids and structures. Volume 115(2022)
• Publication Date: 2022-11
• Subjects: Flow separation -- Backward wave breaking -- Large slope on the free surface; Fluid-structure interaction -- Periodicals; Fluid mechanics -- Periodicals; Structural dynamics -- Periodicals; Structural analysis (Engineering) -- Periodicals; 620.106
• DOI: 10.1016/j.jfluidstructs.2022.103779
• Languages: English
• ISSNs: 0889-9746

Abstract

Abstract: In this work, the backward wave breaking process by the presence of flow separation vortices under a solitary wave is studied. Based on a set of non-dimensional variables defined from the Buckingham Π theorem, a set of numerical experiments are performed in order to analyze the effect of varying the submerged obstacle geometry on the surrounding flow and free surface by using a RANS-VOF model. Model simulations are tested against available experiments showing a good performance of numerical results. The structure-submergence ratio and the structure-based Reynolds number modulate the type of breaking (collapsing-plunging). The structure aspect ratio defines the location and number of backward breaking points for rectangular structures and the breaking wave direction for triangular structures (either forward or backward). Moreover, when the flow separation vortex diameter is comparable to the local water depth a backward wave breaking process is originated. The vortex behaves as a rigid body that accelerates the flow at the upper side of the vortex, accumulating mass at the downstream side where a very large slope on the free surface makes the water fall backward due to gravity.