Article
Mechanics
R. C. Kloosterziel, L. R. M. Maas
Summary: This study introduces a new type of conserved quantity that exists locally at any point in the field, without requiring integration over a specific domain. The pseudo-energy density for non-divergent Rossby waves is derived, showing local invariance for a single plane wave and waves produced by an impulsive point source of vorticity. The anisotropic nature of the energy flux in response to the point source further clarifies the role of the beta plane in the observed western intensification of ocean currents.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
N. Kalligeris, Y. Kim, P. J. Lynett
Summary: Field observations have reported many tsunami-induced eddies in ports and harbors. This study examines the evolution of a turbulent shallow-water monopolar vortex through large-scale experiments and validates a first-order model for predicting the decay and spatial growth of shallow-water vortices. The experiments show the effects of bottom friction and turbulent viscous diffusion on the velocity and radial growth of the vortex flow.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Xinran Zhao, Carlo Scalo
Summary: In this study, the conservation of total helicity through viscous reconnection events in topologically complex vortex flows was investigated using direct numerical simulations. The results demonstrated a clear correlation between helicity annihilation and viscous circulation transfer processes, revealing fundamental hydrodynamic mechanisms responsible for the production/destruction of total helicity during reconnection events.
JOURNAL OF FLUID MECHANICS
(2021)
Letter
Mechanics
G. G. Sutyrin, T. Radko, J. Nycander
Summary: This study examines baroclinic vortices embedded in large-scale vertical shear and describes a new class of stable propagating vortices. These vortices can extract potential energy from a large-scale vertically sheared flow by generating Rossby waves, leading to meridional vortex drift and associated heat flux. The theory is confirmed by numerical simulations, showing that reduced potential vorticity gradient in the upper layer provides favorable conditions for eddy persistence and long-range propagation in westward flows in subtropical oceans.
Article
Mechanics
Peter Frick, Sergei Mandrykin, Vladislav Eltishchev, Ilya Kolesnichenko
Summary: The study investigates the flow of liquid metal induced by electric current in a cylindrical cell, and finds that the ratio of electro-vortex flows and rotational forces affects the evolution of flow structure.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
S. J. Terrington, K. Hourigan, M. C. Thompson
Summary: This article presents a three-dimensional theory of vorticity creation on generalised interfaces, including both non-slip and free-slip boundaries. Vorticity can be created on a boundary by the inviscid relative acceleration between fluid elements on each side of the boundary, driven by either tangential pressure gradients or body forces. Viscosity acts to transfer circulation between the vortex sheet representing the slip velocity on the interface, and the fluid interior, but is not responsible for the creation of vorticity on the interface. This formulation also describes a principle of vorticity conservation for interfacial and free-surface flows.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
S. J. Terrington, K. Hourigan, M. C. Thompson
Summary: Lyman's proposed definition of the boundary vorticity flux offers conceptual benefits in describing the transfer of circulation across a boundary, extending to three-dimensional flows, and enabling control-surface analysis. The definition also illustrates how the kinematic condition of vortex lines not ending in the fluid is maintained, providing an elegant description of viscous processes like vortex reconnection. The examination of flow over a sphere using Lyman's definition demonstrates the benefits of the proposed framework in understanding vortical flow dynamics.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Xuerao He, Zhihao Sun, Mengqi Zhang
Summary: In this study, a sequence of eddies in two-dimensional electrohydrodynamics (EHD) flows of a dielectric liquid is numerically investigated. The results show that the size and intensity of the eddies are related to the electric Rayleigh number (T), with larger T strengthening the vortex intensity and resulting in oscillations in the flow. Additionally, a quantitative comparison between the eddies and theoretical predictions reveals a high level of accuracy.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Adam J. K. Yang, J. Olsthoorn, M. -L. Timmermans
Summary: The vertical transport of sediment in marine environments can be enhanced through a settling-driven convective instability, which is influenced by the presence of horizontal shear. Numerical simulations demonstrate that the transport is determined by the competition between the settling-driven convective instability (Rayleigh-Taylor) and the stratified shear instability (Kelvin-Helmholtz). In the absence of shear, the Rayleigh-Taylor instability drives enhanced vertical sediment transport, while the presence of shear leads to two regimes of effective settling.
Article
Mechanics
Yinan Wang, Xiaowei Zhao, Michael Graham, Juan Li
Summary: The vortex force map method for incompressible viscous flows with multiple bodies is proposed in this research, which can be used to analyze the fluid dynamic forces on individual bodies in a multi-body assembly. By decomposing the fluid force and providing a graphical representation of the vortex-pressure force, the method allows for a comprehensive analysis of the forces acting on each body. The method is applied to a wing-flap starting flow problem, demonstrating its effectiveness in identifying key force-generating regions and directions.
JOURNAL OF FLUID MECHANICS
(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
Meteorology & Atmospheric Sciences
Qiang Wang, Stefano Pierini
Summary: The eddy kinetic energy (EKE) in the Kuroshio Extension (KE) region may be affected by the Kuroshio large meander (KLM) region and the North Pacific Gyre Oscillation (NPGO). Previous studies have shown that the KLM EKE only affects the EKE in the upstream area of KE, while the NPGO has a remarkable effect on the EKE in both upstream and downstream areas. Changes in KLM EKE impact the advection of eddies and the position of the Kuroshio over the Izu Ridge, causing different EKE levels. The NPGO affects KE EKE through the westward propagation of sea surface height anomalies forced by wind stress anomalies associated with the North Pacific Oscillation.
JOURNAL OF CLIMATE
(2023)
Article
Mechanics
G. A. M. van Kuik
Summary: This article introduces the significance of Prandtl's force field method in modern wind energy research and classifies and analyzes which type of body force field generates vorticity and converts energy. In addition, by re-deriving the Kutta-Joukowsky load and the relation between bound and trailing vorticity of a wing, it confirms the consistency between the force field method and the load output analysis method.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
M. V. Kalashnik, O. G. Chkhetiani, M. V. Kurgansky
Summary: This paper introduces new vertically discrete versions of the surface quasigeostrophic (SQG) model with two boundaries, described by two Lagrangian invariants. It is found that for jet flows and vertical shear flows, the instability is absolute, and the most unstable perturbation has a wavelength of the order of the Rossby baroclinic radius of deformation.
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
Environmental Sciences
L. Zavala Sanson, P. Perez-Brunius, J. Sheinbaum
ENVIRONMENTAL RESEARCH LETTERS
(2017)
Article
Mechanics
A. Lopez Zazueta, L. Zavala Sanson
Article
Nanoscience & Nanotechnology
L. M. Flores Ramirez, L. Zavala Sanson
Article
Mechanics
F. Graef, L. Zavala Sanson, L. Plata, J. Ochoa
Article
Mechanics
Jeasson F. Gonzalez, L. Zavala Sanson
Summary: Analytical solutions of barotropic, quasi-geostrophic vortices over an axisymmetric bottom topography are presented, discussing how different topographic profiles affect the vortices. The model results reproduce reasonably well the analytical solutions when the topographic effects are strong enough to inhibit the dipole self-propagation.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Luis Zavala Sanson, Jeasson F. Gonzalez
Summary: This study examines the dynamics of rotating geophysical flows with variable topography, focusing on the effects on intense vortices and the generation of new vortical structures. Numerical simulations and analytical models are used to analyze the quasi-two-dimensional dynamics of such systems. The results show that when encountering submarine mountains, the trajectory of a vortex can be modified and the dipole structure can change, with lower mountains deflecting the vortex towards the anticyclonic side and higher mountains causing the dipole to split into two parts.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Astronomy & Astrophysics
L. Zavala Sanson
Summary: This paper studies the effects of time-dependent mesoscale turbulence on wind-driven ocean circulation and presents numerical simulations of the flow behavior with both large and small-scale forcing terms.
GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS
(2022)
Article
Mechanics
J. Ocampo Jaimes, F. Graef, L. Zavala Sanson
Summary: In this study, the dispersion of particles in two-dimensional vortices, circular monopoles, and the Chaplygin-Lamb dipole was numerically investigated using a Lagrangian stochastic model. The results show that the dispersion behavior of particles varies depending on the flow patterns.
Article
Mechanics
A. H. Duran Colmenares, L. Zavala Sanson
Summary: This article investigates the anisotropic particle dispersion in a continuously forced, two-dimensional turbulent flow on a beta-plane. The study reveals that there is anisotropy in the dispersion of particles under different forcing strengths.
Article
Oceanography
R. C. Cruz-Gomez, L. Zavala Sanson, F. A. Velazquez-Munoz
Summary: A series of rotating tank experiments were conducted to study the behavior of a coastal current encountering a cape and a bay. The experiments revealed that the current surrounds the cape and accumulates negative relative vorticity in front of the downstream bay. The periodicity of the current separation and vortex formation was found to be approximately 16 periods of the rotating system.
CONTINENTAL SHELF RESEARCH
(2023)
Article
Mechanics
Jeasson F. Gonzalez, L. Zavala Sanson
Summary: This study investigates the linear instability of circular vortices over isolated topography in a homogeneous and inviscid fluid using the shallow-water and quasi-geostrophic models on the f-plane. The eigenvalue problem associated with azimuthal disturbances is derived for arbitrary axisymmetric topographies, and amended Rayleigh and Fjortoft theorems are given with topographic effects. The barotropic instability theorems are applied to various nonlinear, quasi-geostrophic solutions of circular vortices over axisymmetric topographic features.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Environmental Sciences
M. F. Gonzalez Amador, L. Zavala Sanson
Summary: This research focuses on studying the surface dispersion of coastal discharges in North America that contribute to the Great Pacific Garbage Patch. Statistical simulations using transition matrices and dispersion ellipses based on historical surface drifter trajectories are used to calculate the evolution of discharged concentration. The study quantifies the preferential routes, arrival times, and relative contributions of each discharge site. It also proposes a new statistical delineation of the position, area, and orientation of the garbage patch. Additional experiments suggest that the retention of debris is influenced by atmospheric conditions, with stronger retention during summer and increased westward dispersal during winter.
MARINE POLLUTION BULLETIN
(2023)
Article
Mechanics
L. Zavala Sanson, I. M. Garcia-Martinez, J. Sheinbaum
Summary: The transfer of momentum between the atmosphere and oceanic motions occurs through the Ekman layer, which is affected by the Earth's rotation. This exchange depends on the surface wind stress and the advection of vorticity due to the Ekman transport. Different mechanisms influence cyclonic and anticyclonic vortices, with top drag mechanism accelerating the decay of anticyclones and vorticity-advection effect reinforcing anticyclones while weakening cyclones.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Geochemistry & Geophysics
Luis Zavala Sanson, Julio Sheinbaum, Paula Perez-Brunius
GEOFISICA INTERNACIONAL
(2018)