Article
Mechanics
Patrick J. R. Folz, Keiko K. Nomura
Summary: This study examines the interaction of two unequal co-rotating viscous vortices in uniform background shear. Different flow regimes of separation and henditions are observed, and the vortex motion and separation strength can be well-predicted by a point-vortex model. The outcomes of merger or straining can be assessed in terms of the starting enstrophy ratio.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
R. B. Nelson, V. S. Krishnamurthy, D. G. Crowdy
Summary: This study examines the shapes and properties of two steadily rotating, equal circulation, two-dimensional hollow vortices, finding a one-parameter family of solutions and comparing the results to a previous study on uniform vorticity patches. It is observed that although the general behavior of the two systems is similar, there are some differences highlighted, especially when the vortices become close to touching.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Anne R. Nielsen, Morten Andersen, Jesper S. Hansen, Morten Brons
Summary: The study investigates vortex pair interactions at low Reynolds numbers, defining vortices based on the Q-criterion and utilizing a topological approach for describing qualitative changes. A general bifurcation theory for Q-vortices is developed to demonstrate a potential threshold for vortex merging when two parameters vary. By considering interactions with two point vortices as initial conditions, it is found that the merging threshold appears as a codimension two bifurcation on a bifurcation curve.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Jie Zhang, Ming-Jiu Ni
Summary: The research found that external magnetic fields have a significant impact on the motion of bubble pairs, especially in terms of direction and strength. The interaction between bubble pairs is influenced by the counter-rotating streamwise vortices during collision, as well as the anisotropic effect of the Lorentz force induced flow diffusion along the magnetic field.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Aerospace
Dominic Schroeder, Thomas Leweke, Ralf Hoernschemeyer, Eike Stumpf
Summary: This study investigates the flow characteristics of the wake behind a rectangular wing using both experimental and numerical methods. By modifying the wingtip geometry with the addition of a perpendicular fin, two closely-spaced tip vortices are generated to reduce the impact of vortices. Velocity measurements were conducted in the near wake of the wing to determine the characteristics of the tip vortex pair, and different configurations of the fin were tested. The results show that a strong and concentrated secondary vortex can only be generated when the fin is placed on the pressure side of the wing. Visualizations and numerical simulations were used to analyze the influence of fin parameter variations on the tip vortex pair.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Biodiversity Conservation
Jun Ma, Jinming Song, Xuegang Li, Qidong Wang, Guorong Zhong
Summary: The study identified a Taylor column around the C4 seamount in the Tropical Western Pacific Ocean, with multidisciplinary indicators confirming its formation. The ecological effects of the Taylor column around the seamount were evident, influencing nutrient distribution and enhancing productivity in the region.
ECOLOGICAL INDICATORS
(2021)
Article
Mechanics
Jian-Zhou Zhu
Summary: A semi-analytical algorithm has been developed to simulate flows with uniform velocity gradient in the real Schur form. The algorithm has been tested in decaying and driven cases, producing basic results and creating cyclone patterns resembling Jovian northern circumpolar cluster.
Article
Chemistry, Physical
Sun-Ah Park, Reddicherla Umapathi, Yun Suk Huh, Woo-Sik Kim
Summary: This study investigates the effect of Taylor vortex wavelength on the polymorphic nucleation and phase transformation of L-histidine. The results show that decreasing the vortex wavelength and increasing the vortex velocity promote stable nucleation and increase the initial polymorphic fraction, leading to a higher rate of phase transformation.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Mechanics
Anne R. Nielsen, Puneet S. Matharu, Morten Brons
Summary: This study explores the evolution of wake topology during the two-dimensional flow past a cylinder undergoing forced transversal oscillations. The transition from two single vortices to a pair and a single vortex shedding per period is investigated. The research reveals the occurrence of topological bifurcations in the vorticity field during this transition, both on the symmetric and asymmetric branches. An extended symbolic classification is introduced to describe the effect of these topological bifurcations, and critical stages in the transition are identified. The robustness of the observed transition process is confirmed through simulations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Meteorology & Atmospheric Sciences
Yansong Liu, Qiang Ren, Fei Yu, Jianfeng Wang, Ran Wang, Feng Nan, Yanan Ding, Tongtong Zheng, Chuanzheng Zhang, Ruixiang Zhao, Hua Zheng, Xiao-Hua Zhu
Summary: Observations and analysis of data from sounders, numerical models, and satellites show the presence of an anticyclonic structure around a seamount in the northwest Pacific, with the Taylor cap induced by impinging flow playing a significant role.
Article
Mathematics, Applied
Suhail Abbas, Abdullah Shah
Summary: This study numerically investigates flow instabilities in a spherical Couette flow system. Different flow states are observed by varying Reynolds number and clearance ratio, and the results are compared with existing research. Additionally, new flow states are discovered.
APPLIED MATHEMATICS AND COMPUTATION
(2022)
Article
Engineering, Environmental
Ye Chan Jee, Woo-Sik Kim, Sang Hyuk Im
Summary: It was demonstrated that the reaction pathway of CsPbBr3 and Cs4PbBr6 perovskite nano crystals (PNCs) can be controlled by the periodic flow fields and precursor ratio. The selective formation of CsPbBr3 and Cs4PbBr6 PNCs was achieved in a Couette-Taylor batch reactor with periodic Taylor vortex flows, while it was not possible in a stirred tank reactor with random turbulent eddy flow.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Mechanics
Darren G. G. Crowdy
Summary: This paper presents a novel theoretical framework for understanding water waves with vorticity without gravity and capillarity. It provides a taxonomy of three subcases and unifies several seemingly unrelated results in the literature. New exact solutions are found, which can be useful for further studies with additional effects.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Jie Yao, Yue Yang, Fazle Hussain
Summary: The study of a slender trefoil knotted vortex reveals that the evolution of the vortex is mainly governed by the change in writhe, rather than twist, although twist plays a significant role in enstrophy growth and energy cascade. Reconnection causes changes in twist helicity and global helicity, strongly dependent on Reynolds number. Flow visualization and helical wave decomposition show the generation of both positive and negative twist helicities before and during reconnection.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
JiaCheng Hu, Sean D. Peterson
Summary: The dynamics of a vortex ring interacting with a solid wall with a coaxial aperture is influenced by the aperture-to-ring radius ratio. The study reveals a 'vortex nozzle' effect when the aperture radius is approximately equal to that of the ring, leading to enhanced impulse and minimized circulation loss during interaction. This phenomenon may have engineering applications in energy harvester designs.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Geosciences, Multidisciplinary
Sabine Haalboom, Henko C. de Stigter, Christian Mohn, Thomas Vandorpe, Marck Smit, Laurens de Jonge, Gert-Jan Reichart
Summary: This study presents different experimental designs for monitoring sediment plumes produced by deep-sea mining. Two field tests were conducted in a shallow setting offshore southern Spain using the Apollo II mining vehicle. The tests provided valuable insights for monitoring nodule mining in the deep Pacific. The plume of suspended sediment was monitored using turbidity sensors deployed on a ship-operated CTD system and on a static array of moored sensors, as well as visually with a ship-operated ROV. The results showed the distribution and behavior of the sediment plume and provided recommendations for monitoring in deep-sea conditions.
Review
Oceanography
Elena Roget, Josep L. Pelegri, Jesus Planella-Morato, Joan Puigdefabregas, Mikhail Emelianov, Ignasi Valles-Casanova, Dorleta Orue-Echevarria
Summary: Diapycnal mixing in the Brazil-Malvinas Confluence Zone (BMC) was assessed based on microstructure measurements during an April 2017 cruise. Active turbulence was observed at all depths and stations, with high-dissipation patches ranging from several metres to a few tens of metres. The frontal zone showed high energy dissipation and eddy diffusivity, with higher values in the south compared to the north of the BMC.
PROGRESS IN OCEANOGRAPHY
(2023)
Article
Environmental Studies
Gala Moreno, Joaquin Salvador, Iker Zudaire, Jefferson Murua, Josep Lluis Pelegri, Jon Uranga, Hilario Murua, Maitane Grande, Josu Santiago, Victor Restrepo
Summary: Fishers and scientists are collaborating to design biodegradable fish aggregating devices (bio-FADs) for efficient fishing in the tropical Pacific, Atlantic, and Indian Oceans. The conventional drifting FAD (dFAD) design, using organic ropes and canvases instead of plastic, has a shorter lifespan due to structural stress. To overcome this, a paradigm shift is proposed to minimize stress by redesigning bio-FAD structures, such as the jelly-FAD, which mimics the buoyancy of jellyfish. Preliminary results show that the jelly-FAD aggregates tuna and has a lifespan of over 6 months at sea, with similar drifting speeds to conventional dFADs.
Article
Geochemistry & Geophysics
A. M. Fedorov, I. L. Bashmachnikov, D. A. Iakovleva, D. A. Kuznetsova, R. P. Raj
Summary: Deep convection in the Subpolar Gyre plays a crucial role in connecting the upper and lower limbs of the Atlantic Meridional Overturning Circulation. The intensity of convection is estimated using mixed layer depth and vertical profiles of potential density. The robustness of these estimates needs to be verified before studying the inter-annual variability of deep convection. Three convection domains with high frequencies of deep convection events were identified in the Subpolar Gyre, and a sufficient number of profiles were collected for these domains. However, continuous time series of convection intensity are only available since the mid-2000s.
DYNAMICS OF ATMOSPHERES AND OCEANS
(2023)
Article
Engineering, Ocean
Anna Olive Abello, Josep L. Pelegri, Francisco Machin
Summary: A simple model-dependent approach called the radial offset by diffusion (ROD) method is proposed for estimating horizontal diffusivity in the southwestern South Atlantic. The method compares actual displacements of field drifters with numerical trajectory predictions to determine the diffusive motions not captured by the numerical model. The ROD method is validated for both numerical and field applications.
JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Ludmila Caetano, Carles Guallar, Jacobo Martin, Montserrat Vidal, Leticia Cotrim da Cunha, Rosemary Vieira, Leonardo Amora-Nogueira, Josep L. Pelegri, Humberto Marotta
Summary: This study investigates the small-scale distribution of pCO2 in the subantarctic Atlantic Patagonian waters, specifically in the Argentinian Beagle Channel. The findings suggest the persistence of pCO2 below atmospheric equilibrium in this area and reveal the influences of physical and biological factors, such as temperature, salinity, and chlorophyll-a fluorescence, on the variability of pCO2. The study also highlights the importance of metabolic and physical controls on the sequestration of atmospheric carbon in subpolar coastal waters.
JOURNAL OF MARINE SYSTEMS
(2023)
Article
Oceanography
D. A. Iakovleva, I. L. Bashmachnikov, D. A. Kuznetsova
Summary: In this study, the impact of AMOC variability on the water temperature of the North Atlantic and Arctic Ocean's upper 100-m layer is investigated. Three datasets with different spatial resolutions and coverage of different time periods are used. The study finds that the second EOF of temperature variability, which accounts for 20-27% of the variance, is associated with changes in AMOC intensity. The AMOC has the highest impact on water temperature in the Irminger and Labrador seas, with fluctuations reaching 1.5-2 degrees C in the central Irminger Sea.
Review
Oceanography
Christian Mohn, Jorgen L. S. Hansen, Marina Carreiro-Silva, Stuart A. Cunningham, Evert de Froe, Carlos Dominguez-Carrio, Stefan Gary, Ronnie N. Glud, Cordula Goke, Clare Johnson, Telmo Morato, Eva Friis Moller, Lorenzo Rovelli, Kirstin Schulzi, Karline Soetaert, Anna van der Kaaden, Dick van Oevelen
Summary: Cold-water corals (CWCs) thrive in areas with complex and rough topography, but little is known about how basin-scale changes in the ocean climate affect their growth. In this study, high-resolution hydrodynamic models were used to investigate the impact of variations in basin-scale currents on local hydrodynamics and CWC communities. It was found that the variability of near-bottom currents and water mass properties at different AMOC states strongly influenced the CWC distribution. The kinetic energy dissipation rate was proposed as a mechanistic descriptor of CWC presence, providing insight into the hydrodynamics driving organic matter supply to these communities.
PROGRESS IN OCEANOGRAPHY
(2023)
Article
Geochemistry & Geophysics
Ismail Mondal, Aakash De, Subhanil Nandi, Sandeep Thakur, Mini Raman, Felix Jose, Tarun Kumar De
Summary: The study aims to assess variations in spatio-temporal characteristics of water quality parameters in three tropical estuaries in the Indian Sundarbans. The accuracy of the C2RCC processor in diverse bio-optical regimes was tested, and a good correlation between OLCI data and in situ measurements was observed. The study demonstrates the efficacy of using Sentinel 3 OCLI data for remote sensing applications in shallow marine and estuarine environments.
Article
Oceanography
E. W. Willcox, J. Bendtsen, J. Mortensen, C. Mohn, M. Lemes, T. J. Pedersen, J. Holding, E. F. Moller, M. K. Sejr, M. S. Seidenkrantz, S. Rysgaard
Summary: This study presents a synoptic survey of the Northeast Greenland shelf and slope during late summer 2017, investigating hydrography, nutrients, conservative tracers, and climate factors. The results indicate that the Laptev Sea is a major freshwater source in the region during this period, and there is no conclusive evidence of Pacific Water. The observations suggest a direct link between Northeast Greenland hydrology and processes occurring on Eurasian shelves.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
Dorleta Orue-Echevarria, Kurt L. Polzin, Alberto Naveira C. Garabato, Alexander Forryan, Josep L. Pelegri
Summary: This study evaluates the rates of isopycnal stirring, water mass transport, and diapycnal mixing across the Brazil-Malvinas Confluence (BMC) using microstructure and hydrographic measurements. The results show widespread isopycnal stirring and weak diapycnal mixing in the BMC, with isopycnal stirring prevailing in deeper layers. Eddies are found to have an important cross-BMC transport, suggesting that eddy-induced flows significantly contribute to the transfer of waters in the region.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
Cristina Arumi-Planas, Maria Dolores Perez-Hernandez, Josep L. Pelegri, Pedro Velez-Belchi, Mikhail Emelianov, Veronica Cainzos, Luis Cana, Yvonne L. Firing, Luis Garcia-Weil, Daniel Santana-Toscano, Alonso Hernandez-Guerra
Summary: The South Atlantic Ocean plays a crucial role in the heat exchange of the climate system by hosting the returning flow of the Atlantic Meridional Overturning Circulation (AMOC). Through data analysis from hydrographic cruises, we have identified different water masses and calculated their circulation patterns in the South Atlantic Subtropical gyre. We have also assessed the strength of the AMOC, heat transport, and freshwater flux in this region.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
I. L. Bashmachnikov, R. P. Raj, P. Golubkin, I. E. Kozlov
Summary: This study compares the statistics of mesoscale eddies in the Norwegian and Greenland Seas, finding that eddies in the central Greenland Sea are less intense and have smaller heat anomalies compared to those in the Norwegian Sea. The study also confirms the significant impact of eddies generated from the Norwegian Atlantic Slope Current on heat transport to the Arctic.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Meteorology & Atmospheric Sciences
D. A. Iakovleva, I. L. Bashmachnikov
Summary: This paper examines the mechanisms of the variability of oceanic heat flux in the Norwegian Current and finds that the variability is associated with that of the water transport, which is governed by the variability of the sea level gradient across the Norwegian Current.
IZVESTIYA ATMOSPHERIC AND OCEANIC PHYSICS
(2023)
Article
Oceanography
A. S. Kaledina, I. L. Bashmachnikov
Summary: This study aims to reveal the spatial and temporal variability of density inversions in the Greenland Sea and propose the mechanisms of their formation during the cold seasons from 1993 to 2019, which helps understand the variation in convection intensity in the sea.
PHYSICAL OCEANOGRAPHY
(2023)
Article
Oceanography
Jason A. Law, Robert H. Weisberg, Yonggang Liu, Dennis A. Mayer, Jeffrey C. Donovan
Summary: Time series data from a moored array of sensors are used to describe the long-term mean circulation and seasonal variations on the West Florida Continental Shelf. The observations reveal a coherent shelf-wide circulation pattern with alongshore and down-coast flow, and a coastal jet separating an upwelling region from a downwelling region influenced by the deeper ocean.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2024)