| Title: |
Tridimensional nonhydrostatic transient rip currents in a wave-resolving model |
| Authors: |
Marchesiello, Patrick; Auclair, Francis; Debreu, Laurent; Mcwilliams, James, C.; Almar, Rafael; Benshila, Rachid; Dumas, Franck |
| Contributors: |
Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS); Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3); Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS); Laboratoire d'aérologie (LAERO); Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Communauté d'universités et établissements de Toulouse (Comue de Toulouse)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS); Mathematics and computing applied to oceanic and atmospheric flows (AIRSEA); Centre Inria de l'Université Grenoble Alpes; Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Grenoble Alpes (UGA)-Laboratoire Jean Kuntzmann (LJK); Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP); Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP); Université Grenoble Alpes (UGA); Department of Atmospheric and Oceanic Sciences Los Angeles (AOS); University of California Los Angeles (UCLA); University of California (UC)-University of California (UC); Service Hydrographique et Océanographique de la Marine (SHOM); Ministère des armées – Ministère de la défense France (1946-.); This research has received support from a consortium of French research agencies, as part of CROCO’s development project (GdR CROCO). It was granted access to the HPC resources of CALMIP supercomputing center under allocation P19069. The fieldwork received support by the French INSU/EC2CO program (Grand Popo Experiment). We also thank H. Michallet for sharing the GLOBEX data, now freely available at zenodo.org/record/4009405. Apart from these, all data were acquired by the authors and the CROCO source code is freely available at www.croco-ocean.org. Both observational and modeling data are available upon request. |
| Source: |
ISSN: 1463-5003 ; Ocean Modelling ; https://inria.hal.science/hal-02883697 ; Ocean Modelling, 2021, 163, pp.101816. ⟨10.1016/j.ocemod.2021.101816⟩ ; https://www.sciencedirect.com/science/article/pii/S1463500321000676. |
| Publisher Information: |
CCSD; Elsevier |
| Publication Year: |
2021 |
| Collection: |
Université Toulouse III - Paul Sabatier: HAL-UPS |
| Subject Terms: |
Wave-resolving LES model; Turbulent cascade; Rip currents; Surfzone; wave-resolving model; nonhydrostatic; transient rip; 3D instability; [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation |
| Description: |
International audience ; Flash rips and surf eddies are transient horizontal structures of the order of 10 to 100 m, which can be generated in the surfzone in the absence of bathymetric irregularities. They are traditionally evaluated in a depth averaged setting which involves intrinsic horizontal shear instabilities and the direct generation of vorticity by short-crested waves. In this article, we revisit the processes of surf eddy generation with a new three-dimensional wave resolution model (CROCO) and provide a plausible demonstration of new 3D non-hydrostatic instability and turbulent cascade. We first present a quick overview of a compressible free surface approach suitable for nearshore dynamics. Its ability to simulate the propagation of surface gravity waves and nearshore wave-driven circulation is validated by two laboratory experiments. Next, we present a real world application from Grand Popo Beach, Benin, forced by waves with frequency and directional spreading. The generation of surf eddies by the 3D model differs from depth-averaged models, due to the vertical shear associated with shallow breaking waves. In this case, the generation of eddies from both horizontal shear instability and the breaking of short-crested waves is hampered, the former by stretching the along shore current and the latter by inhibiting the inverse energy cascade. Instead, the vertical shear flow is subjected to forced wave group variability and Kelvin-Helmholtz type instability at an inflection point. Primary and secondary instabilities generate spanwise and streamwise vorticity connecting small-scale eddies to larger horizontal surfzone structures. Streamwise filaments, appearing as 5 m wide ribs or mini-rips, can extend beyond the surfzone but with moderate energy. These results appear consistent with the velocity spectra and observed patterns of tracers and suspended sediments at Grand Popo Beach. The timescale associated with the mean shear-induced turbulence is several times the wave period and suggests an ... |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
IRD: fdi:010082094 |
| DOI: |
10.1016/j.ocemod.2021.101816 |
| Availability: |
https://inria.hal.science/hal-02883697; https://inria.hal.science/hal-02883697v3/document; https://inria.hal.science/hal-02883697v3/file/Wave_resolving_CROCO.pdf; https://doi.org/10.1016/j.ocemod.2021.101816 |
| Rights: |
info:eu-repo/semantics/OpenAccess |
| Accession Number: |
edsbas.A360886C |
| Database: |
BASE |