Article
Mechanics
M. R. Jalali, D. G. Dritschel
Summary: The article discusses obtaining a single-layer flow model with non-hydrostatic effects when the hydrostatic assumption of the shallow-water model is dropped. In rotating flows, non-hydrostatic effects become important when the Rossby deformation length is comparable to the depth of the fluid layer, leading to compression of inertia-gravity waves and reduction in group velocity.
Review
Mechanics
Bishakdatta Gayen, Ross W. Griffiths
Summary: The differences in temperature and buoyancy flux at the ocean surface have a global impact on convection and circulation in the oceans, as well as the density difference from top to bottom. This surface-forced convection is different from other types of convection and the role of buoyancy forcing in the oceans is not well understood. The dynamics of this convection play a crucial role in the large-scale horizontal circulation on Earth.
ANNUAL REVIEW OF FLUID MECHANICS
(2022)
Article
Oceanography
Yeqiang Shu, Jinghong Wang, Huijie Xue, Rui Xin Huang, Ju Chen, Dongxiao Wang, Qiang Wang, Qiang Xie, Weiqiang Wang
Summary: Strong subinertial variability near a seamount in the South China Sea was revealed by mooring observations. The study found that topographic Rossby waves (TRWs) and deep eddies were the main factors causing this variability, explaining a significant portion of the kinetic energy of the deep subinertial currents. The generation of TRWs was induced by mesoscale perturbations in the upper layer, while the interaction between cyclonic-anticyclonic eddy pairs and the seamount topography contributed to the generation of deep eddies.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Engineering, Marine
Oscar Castro-Orgaz, Francisco N. Cantero-Chinchilla, Willi H. Hager
Summary: This study develops high-order shallow water expansions for flows over uneven beds and applies them to the overflow process. The solutions are compared with experimental results and shown to be better than existing theories in terms of accuracy and theoretical validity.
Article
Meteorology & Atmospheric Sciences
Agatha M. de Boer, David K. Hutchinson, Fabien Roquet, Louise C. Sime, Natalie J. Burls, Celine Heuze
Summary: This study investigates the impact of Southern Ocean bathymetry on the coupled ocean-atmosphere system. By systematically removing major topographic barriers in a coupled climate model, the researchers find that the removal of these barriers affects various components of the climate system, such as the Antarctic Circumpolar Current (ACC) pathways, sea surface temperature, precipitation, and winds. The findings provide a better understanding of the importance of bathymetry in controlling the pathways of the ACC and its significance for climate.
JOURNAL OF CLIMATE
(2022)
Article
Mechanics
Jake Langham, Mark J. Woodhouse, Andrew J. Hogg, Jeremy C. Phillips
Summary: This study investigates the linear stability properties of shallow-layer overland flow models with morphodynamics and sedimentary phase motion. It finds that naive formulations of morphodynamics can lead to mathematically ill-posed governing equations, which can be resolved by including neglected physical processes such as turbulent momentum diffusion and bed load sediment transport. The study also shows that steady morphodynamic flows can bifurcate into dilute and concentrated states, with different stability behaviors in response to concentration disturbances.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Geosciences, Multidisciplinary
Yan Du, Fan Wang, Tianyu Wang, Weiwei Liu, Linlin Liang, Ying Zhang, Yunfan Chen, Jiaxing Liu, Wei Wu, Kefu Yu, Jing Zhang
Summary: The Indo-Pacific Convergence Zone is a complex ocean dynamical system that links basin-scale circulations in the Pacific and Indian Oceans. It plays a crucial role in regulating atmospheric circulations and global climate events. Additionally, it has direct impacts on biodiversity and ecological processes.
EARTH-SCIENCE REVIEWS
(2023)
Article
Oceanography
Yu Hong, Ying Zhang, Yan Du
Summary: The Southern Ocean is an important region for absorbing and storing anthropogenic heat. This study focuses on the south Indian Ocean and finds distinct warming minimum/cooling and freshening in the subtropical ocean thermocline. The freshening anomaly is advected to the north and subducted into the ocean interior, leading to fresher, deeper, and cooler isopycnal surfaces. This has implications for the future heat storage in the Southern Ocean.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Oceanography
Haihong Guo, Michael A. Spall
Summary: The study focused on wind-driven exchange between marginal seas and open oceans, finding strong baroclinic flows along island boundaries with maximum transport in gaps. Topography around islands alters current pathways but cannot ultimately limit total wind-driven exchange.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Oceanography
Aviv Solodoch, Andrew L. Stewart, James C. McWilliams
Summary: Long-lived anticyclonic eddies trapped in bowl-like topographic depressions in the North Atlantic basins have been observed in numerical simulations, exhibiting distinct characteristics under different nonlinearity parameters. These findings suggest the emergence of a novel circulation pattern governed by potential vorticity segregation mechanisms, challenging previous theories of mesoscale turbulence over topography and highlighting the importance of initial conditions in determining the intensity and vertical distribution of the trapped eddies.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Engineering, Marine
Shengxiao Zhao, Chunning Ji, Zhenzhou Sun, Huafeng Yu, Zhimeng Zhang
Summary: Local scour around two tandem piles in shallow water was numerically investigated, and the results showed that the scour process, depth, and flow fields were significantly influenced by the pile gap ratio and water depth ratio. Increasing the water depth ratio led to larger scour dimensions and maximum scour depths, and the scour patterns differed between the front and rear piles under different water depth conditions.
Article
Mechanics
W. Liu, H. Hassanzadeh, F. Larachi, S. M. Taghavi
Summary: We experimentally investigate buoyant immiscible displacement flows in a rotating pipe and analyze key flow features using image processing and ultrasound Doppler velocimetry techniques. The emergence of heavy fluid fronts and the effect of rotation speed on the displacement flows are observed. Dimensional analysis reveals that the displacement flow is governed by four dimensionless parameters. The classification of flow regimes and interfacial instabilities are achieved, and the Kelvin-Helmholtz instability is found to be the main interfacial instability. The velocity fields in stationary and rotating pipes are found to have remarkable differences, and the Fourier transform approach provides a preliminary understanding of concentration waves and amplitudes.
Article
Geosciences, Multidisciplinary
Ming Feng, Nick Caputi, Arani Chandrapavan, Miaoju Chen, Anthony Hart, Mervi Kangas
Summary: Ocean temperature variability off the west coast of Australia is influenced by various climate variability modes, with a shift to a multi-year cold phase following the unprecedented Ningaloo Nino event. This marine cold-spell has facilitated the recovery of local fisheries species impacted by previous marine heatwaves.
JOURNAL OF MARINE SYSTEMS
(2021)
Article
Multidisciplinary Sciences
D. Gwyn Evans, Eleanor Frajka-Williams, Alberto C. Naveira Garabato
Summary: This study finds that small-scale turbulence generated when eddy flow impacts the steep and corrugated slope of an ocean western boundary plays a dominant role in the regional decay of mesoscale eddy kinetic energy. Comparison with measurements of turbulent dissipation shows that the decay rate of mesoscale eddies is similar to the observed turbulent dissipation rate. This demonstrates the effective transfer of mesoscale eddy kinetic energy to small, dissipative scales triggered by the eddies' interaction with the western boundary topography.
SCIENTIFIC REPORTS
(2022)
Article
Mechanics
Jim Thomas, Lingyun Ding
Summary: We investigate the inverse flux of waves in a one-dimensional rotating shallow water model, a simplified geophysical fluid dynamics model. By directly integrating the governing equations, we observe that waves injected at small scales primarily transfer upscale through resonant quartic interactions between wave modes. The upscale transfer of waves is found to be non-local and involves turbulent transfer between different scales of the flow. Our analysis reveals intermittent bursts in wave action flux, resulting in a shallower wave spectrum and higher amplitude wave fields in physical space. Additionally, statistics of the flow fields indicate that lower energy high wavenumbers follow the assumptions of wave turbulence theory, while non-uniform wave phase distribution and non-Gaussian statistics dominate at larger scales or low wavenumbers containing the majority of the flow energy. These findings highlight the complex and intricate features associated with the upscale transfer of waves in the simple geophysical fluid dynamic model of one-dimensional rotating shallow water that have not been previously recognized.
JOURNAL OF FLUID MECHANICS
(2023)