Numerical Modeling of Flow and Bed Evolution of Bichromatic Wave Groups on an Intermediate Beach Using Nonhydrostatic XBeach

• Published in: Journal of waterway, port, coastal, and ocean engineering Vol. 146; no. 1
• Main Authors: Ruffini, Gioele, Briganti, Riccardo, Alsina, José M, Brocchini, Maurizio, Dodd, Nicholas, McCall, Robert
• Format: Journal Article
• Language: English
• Published: New York American Society of Civil Engineers 01-01-2020
• Subjects: Beaches; Boundary conditions; Computational fluid dynamics; Computer simulation; Error analysis; Fluid flow; Frequency measurement; High frequency; Hydrodynamics; Incident waves; Long waves; Modelling; Offshore; Sediment transport; Sediments; Surf zone; Technical Papers; Transport; Wave groups
• ISSN: 0733-950X; 1943-5460
• DOI: 10.1061/(ASCE)WW.1943-5460.0000530

AbstractThis paper analyzes the modeling of the hydro- and morphodynamics of bichromatic wave groups on an intermediate beach with an initial 1∶15 slope. The nonhydrostatic version of XBeach was used to simulate two incident wave conditions of the experiments carried out within the HYDRALAB-IV Coupled High Frequency Measurement of Swash Sediment Transport and Morphodynamic (CoSSedM) project. The chosen forcing conditions have different strengths of swash–swash interaction. A procedure was developed to generate boundary conditions for the model that are able to fully account for both the bound and free long waves measured during the experiments. Using the normalized root-mean-squared error as a measure, this paper finds a higher accuracy of the nonhydrostatic version of XBeach in simulating swash–swash interaction from the hydrodynamics point of view, and worse performances in capturing the details of intragroup sediment transport. Nevertheless, the model is able to distinguish the relative difference in offshore swash sediment transport among different types of swash–swash interaction, and it is overall more successful in simulating beach morphodynamics when the swash sediment transport is of the same order of magnitude as the surf zone one.