Article
Mechanics
Wouter J. T. Bos
Summary: The study focuses on three-dimensional turbulence without vortex stretching, showing a system that conserves enstrophy but not kinetic energy, with enstrophy transferred to small scales by a direct cascade using spectral closure. In the inviscid truncated system, enstrophy tends towards equipartition over wave vectors without observing an inverse cascade once scales larger than the forcing scale reach equipartition.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Astronomy & Astrophysics
Pallavi Bhat, Muni Zhou, Nuno F. Loureiro
Summary: Recent numerical studies have shown the existence of inverse transfer of magnetic energy in 3D magnetically dominated turbulence, likely driven by magnetic reconnection. The scaling behavior is found to be similar between 2D and 3D cases. Furthermore, simulations also demonstrate an inverse transfer of magnetic energy in 3D when the magnetic field is subdominant to the flow, with the emergence of a dynamo effect.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Yue Hu, A. Lazarian
Summary: In this study, the three-dimensional magnetic field of the low-mass star-forming region L1688 is measured for the first time using (CO)-C-12, (CO)-C-13, (CO)-O-18, H I, and polarized dust emissions. The magnetic field is found to have different inclination angles in different regions of L1688. The orientation of the magnetic field is statistically coherent and the cloud is potentially undergoing gravitational contraction and collapse.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Jens Kleimann, Sean Oughton, Horst Fichtner, Klaus Scherer
Summary: We propose a time-dependent, three-dimensional single-fluid model to study the transport of magnetohydrodynamic (MHD) turbulence in the outer heliosphere, which is evolving self-consistently with a dynamic large-scale solar wind. We focus on the region beyond the termination shock, where the solar wind expands subsonically, as well as sub-Alfvenically and nonradially. We refine the treatment of turbulence by considering a nonconstant energy difference and allowing each quantity its own characteristic correlation length scale.
ASTROPHYSICAL JOURNAL
(2023)
Article
Mechanics
Miguel P. Encinar, Javier Jimenez
Summary: The algorithm introduced by Jimenez (J. Fluid Mech., vol. 854, 2018, R1) is used to identify the flow patterns of causal significance in three-dimensional isotropic turbulence. The study finds that the dimensions of the perturbations introduced in the flow are controlled by the kinetic energy content and the enstrophy and dissipation, and affect their significance in the flow. Strain is found to be more efficient than vorticity in propagating the perturbation contents to other regions of the flow. The findings suggest that manipulating strain-dominated vortex clusters is more effective in controlling turbulent flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Physics, Fluids & Plasmas
J. F. Parisi, F. I. Parra, C. M. Roach, M. R. Hardman, A. A. Schekochihin, I. G. Abel, N. Aiba, J. Ball, M. Barnes, B. Chapman-Oplopoiou, D. Dickinson, W. Dorland, C. Giroud, D. R. Hatch, J. C. Hillesheim, J. Ruiz Ruiz, S. Saarelma, D. St-Onge
Summary: Nonlinear multiscale gyrokinetic simulations are used to study the three-dimensional structure of electron-temperature-gradient (ETG) turbulence in a Joint European Torus edge pedestal. The simulations show that the turbulence varies strongly according to the local magnetic-field configuration, and has different wavelength characteristics in the parallel and perpendicular directions.
Article
Mechanics
Aditi Sengupta, Prasannabalaji Sundaram, Vajjala K. Suman, Tapan K. Sengupta
Summary: Rayleigh-Taylor instability refers to the instability that occurs when the interface between two fluids of different densities is removed and the heavier fluid rests on top of the lighter fluid in the equilibrium state. This instability has been observed at various length scales, from nuclear fusion to astrophysical phenomena like supernova explosions. A non-overlapping parallel algorithm is used to simulate the three-dimensional Rayleigh-Taylor instability problem, providing insights into the vorticity creation and the dominance of viscous terms in the compressible flow.
Article
Mechanics
A. Gorbunova, G. Balarac, L. Canet, G. Eyink, V. Rossetto
Summary: The study uses direct numerical simulations to test recent theoretical predictions in a three-dimensional incompressible fluid. Results show agreement with predictions from the Functional Renormalization Group (FRG) and can be explained as a consequence of sweeping. Additionally, there is a crossover in the two-point spatiotemporal correlations of the velocity modulus from Gaussian to exponential decay.
Article
Oceanography
Tomoyuki Takabatake, Dawn Chenxi Han, Justin Joseph Valdez, Naoto Inagaki, Martin Mall, Miguel Esteban, Tomoya Shibayama
Summary: This study investigates the characteristics of partially submerged landslide-tsunamis through laboratory experiments and develops a predictive equation to estimate their heights. The results show that wave amplitude, period, celerity, and wavelength do not vary significantly according to propagation angles, but wave dispersion has a significant impact on the propagation process. The volume of a landslide has a greater effect on the height of a partially submerged landslide-tsunami than other parameters.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Nanoscience & Nanotechnology
Claire Donnelly, Aurelio Hierro-Rodriguez, Claas Abert, Katharina Witte, Luka Skoric, Dedalo Sanz-Hernandez, Simone Finizio, Fanfan Meng, Stephen McVitie, Jorg Raabe, Dieter Suess, Russell Cowburn, Amalio Fernandez-Pacheco
Summary: The design of complex magnetic systems through nonlinear interactions or three-dimensional geometries can achieve new functionalities by controlling intrastructure properties and magnetostatic coupling of neighboring magnetic structures. This can lead to new physics and functionalities, such as three-dimensional chiral spin states and spin textures with new spin topologies.
NATURE NANOTECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
A. Mathews, J. W. Hughes, J. L. Terry, S. G. Baek
Summary: This study presents a physics-informed deep learning approach for calculating turbulent electric fields in a two-dimensional fusion plasma. The results are consistent with theoretical models and experimental estimates, and demonstrate the influence of locally puffed helium on the correlation between electric field and electron pressure.
PHYSICAL REVIEW LETTERS
(2022)
Article
Optics
David Blinder, Takashi Nishitsuji, Peter Schelkens
Summary: In this study, we propose a new algorithm for computing computer-generated holography (CGH) for arbitrary 3D curves using splines. Compared to previous solutions, which only drew planar curves, our algorithm achieves high efficiency and can generate real-time 4K holographic videos of complex 3D curved objects.
Article
Mechanics
Jianghua Li, Bofu Wang, Xiang Qiu, Jianzhao Wu, Quan Zhou, Shixiao Fu, Yulu Liu
Summary: The flow past a cylinder in proximity to a plane wall is numerically investigated for small gap ratios, and three vortex dynamics processes associated with different hairpin vortex generation mechanisms are identified for the first time. The wake-induced turbulent transition is also analyzed in this study. The findings provide important insights into the vortex dynamics of cylinder flow, and contribute to a better understanding of the flow behavior.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Environmental
Fei Wu, Mengyun Ling, Lingyun Wan, Pei Liu, Yabin Wang, Qiuyu Zhang, Baoliang Zhang
Summary: In this study, two metal-organic frameworks composite nanoflowers with anisotropic binary assembled structures were constructed using a facile one-pot method. The optimized absorbers exhibited outstanding microwave absorption performance, with rich heterogeneous interfaces, porous structure, suitable impedance matching, and complementary loss mechanisms.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Multidisciplinary Sciences
Xinmin Li, Rongsheng Wang, Quanming Lu, Christopher T. Russell, San Lu, Ian J. Cohen, R. E. Ergun, Shui Wang
Summary: In the process of magnetotail reconnection, super-thermal electrons are observed within the X-line region, indicating effective acceleration due to turbulence. The study presents direct evidence of these electrons and observes a dynamic filamentary current network in electron scale.
NATURE COMMUNICATIONS
(2022)
Review
Mechanics
Eric Falcon, Nicolas Mordant
Summary: In the past decade, there has been a significant increase in wave turbulence studies, particularly in the field of water waves. The theoretical modeling of ocean waves, which has driven the development of weak turbulence theory, has been found to be too idealized to capture experimental observations. Laboratory observations have revealed that the waves studied are actually gravity-capillary waves, as opposed to ocean waves. This richer physics has led to various physical effects beyond the theoretical framework, especially in the gravity-capillary crossover region.
ANNUAL REVIEW OF FLUID MECHANICS
(2022)
Article
Mechanics
Ram Sudhir Sharma, Michael Berhanu, Arshad Kudrolli
Summary: The study demonstrates the conditions for cave-like features on dissolving cliffsides and shows that alcoves with tapered bottoms and sharp-edged ceilings develop on vertical solid surfaces dissolving in aqueous solvents. The evolution of sufficiently large indentations into alcoves is controlled by a solutal Rayleigh-Bénard density inversion instability.
Article
Physics, Fluids & Plasmas
Alexey Tikan, Felicien Bonnefoy, Giacomo Roberti, Gennady El, Alexander Tovbis, Guillaume Ducrozet, Annette Cazaubiel, Gaurav Prabhudesai, Guillaume Michel, Francois Copie, Eric Falcon, Stephane Randoux, Pierre Suret
Summary: The Peregrine soliton (PS) is a prototype nonlinear structure that captures the properties of rogue waves. Recent research has shown that the PS can emerge independently of its solitonic content from partially radiative or solitonless initial data. In this study, the researchers controlled the occurrence of the PS in space-time by adjusting the initial chirp. The proposed method of nonlinear spectral engineering was found to be robust to higher-order nonlinear effects.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Physics, Multidisciplinary
Filip Novkoski, Chi-Tuong Pham, Eric Falcon
Summary: We report on the experimental observation of solitons propagating along a torus of fluid. We show that such a periodic system leads to significant differences compared to the classical plane geometry, including the observation of subsonic elevation solitons and a nonlinear dependence of soliton velocity on its amplitude. By imposing periodic boundary conditions onto the KdV equation, we recover these observations. Our work reveals the importance of periodicity for studying solitons and validates a nonlinear spectral analysis method in this periodic geometry.
Article
Mechanics
Guillaume Michel, Felicien Bonnefoy, Guillaume Ducrozet, Eric Falcon
Summary: This study investigates the statistics of rogue waves occurring in the inverse cascade of surface gravity wave turbulence. It reveals that in statistically homogeneous, stationary and isotropic wave fields, low-frequency waves are generated by nonlinear interactions instead of direct forcing. The analysis of thousands of rogue waves shows that certain properties crucially depend on four-wave resonant interactions, with larger crests being more likely than predicted by second-order models.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Physics, Multidisciplinary
Jean-Baptiste Gorce, Eric Falcon
Summary: We experimentally investigate 3D hydrodynamic turbulence at scales larger than the forcing scale and manage to separate the forcing scale from the container size. Our results show that the large-scale dynamics are in statistical equilibrium and can be described using an effective temperature, though not isolated from the turbulent Kolmogorov cascade.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Michael Berhanu, Simon Merminod, Gustavo Castillo, Eric Falcon
Summary: This study investigates fluid-like and crystal-like states in a driven granular material. The findings reveal collective excitations characterized by dispersion relations, analogous to phonons in condensed matter, propagate in the system. When the magnetic coupling is weak, the waves are longitudinal, while both longitudinal and transverse waves propagate when the coupling is stronger, similar to solid-like phases.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Multidisciplinary Sciences
Alexey Tikan, Felicien Bonnefoy, Guillaume Ducrozet, Gaurav Prabhudesai, Guillaume Michel, Annette Cazaubiel, Eric Falcon, Francois Copie, Stephane Randoux, Pierre Suret
Summary: In this study, we numerically and experimentally investigate the concept of nonlinear dispersion relation (NDR) in the context of partially coherent waves propagating in a one-dimensional water tank. The NDR of the slowly varying envelope of the deep-water waves is accurately measured using a limited number of wave gauges, providing precise characterization of frequency shift and NDR broadening, as well as revealing the presence of solitons. Our analysis shows that the shape and broadening of the NDR can indicate deviation from integrable turbulence induced by high order effects in experiments. We also compare our experimental observations with numerical simulations.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Fluids & Plasmas
Guillaume Ricard, Eric Falcon
Summary: We experimentally observe a transition from dispersive wave turbulence to a nondispersive regime involving shock waves on a fluid surface. By tuning the dispersivity of the system using a magnetic fluid in a canal subjected to an external horizontal magnetic field, we observe gravity-capillary wave turbulence at low magnetic field and random steep coherent structures which are shock waves at high enough field. These shock waves generate singularities in the second-order difference of the surface elevation and exhibit an omega-4 frequency power spectrum.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Physics, Fluids & Plasmas
Jules Fillette, Stephan Fauve, Eric Falcon
Summary: We report on an experimental study of axisymmetric gravity-capillary standing waves generated by a vertically vibrating ring partially immersed into a fluid. Different regimes of standing waves are observed at the basin center depending on the forcing parameters: linear, nonlinear, and ejection regimes. The experimental spatial profile of standing waves breaks the up-down symmetry for stronger forcing and is well described by a third-order nonlinear theory. Furthermore, the maximum height of the wave crest at the basin center increases linearly with its wavelength as the forcing is further increased, due to the saturation of its steepness, which is well captured by a proposed model.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Physics, Fluids & Plasmas
Filip Novkoski, Chi-Tuong Pham, Eric Falcon
Summary: We observe the nonlinear three-wave resonant interactions between the gravity-capillary and sloshing modes of hydrodynamic waves. A triadic resonance instability is observed, with exponential growth and phase locking. The efficiency of the interaction is highest when the gravity-capillary phase velocity matches the group velocity of the sloshing mode. Additional waves are generated through a cascade of three-wave interactions for stronger forcing, filling the wave spectrum. This mechanism may have relevance in systems involving multiple propagation modes.
Article
Physics, Fluids & Plasmas
Jean-Baptiste Gorce, Eric Falcon
Summary: In this study, we investigate the dynamics of magnets in a fluid under the influence of a vertical oscillating magnetic field. Unlike previous studies on granular gas, where energy is injected by vibrating the boundaries, our system does not show cluster formation, orientational correlation, and equipartition of energy. The linear velocity distributions of the magnets exhibit stretched exponentials, similar to boundary-forced dry granular gas systems, but the exponent is independent of the number of magnets. The conversion rate of angular momentum into linear momentum during collisions plays a crucial role in controlling the dynamics of this homogenously forced granular gas. We also compare our findings with ideal gas and nonequilibrium boundary-forced dissipative granular gas systems.
Article
Physics, Fluids & Plasmas
Evgeny Kochurin, Guillaume Ricard, Nikolay Zubarev, Eric Falcon
Summary: We present a three-dimensional direct numerical simulation of wave turbulence on the free surface of a magnetic fluid under an external horizontal magnetic field. We observe a transition from capillary-wave turbulence to anisotropic magneto-capillary wave turbulence with increasing magnetic field strength. At high enough magnetic field, the wave turbulence becomes highly anisotropic, cascading predominantly perpendicular to the field direction. This finding is in good agreement with the prediction of a phenomenological model and with anisotropic Alfven wave turbulence. Although surface waves on a magnetic fluid differ from Alfven waves in plasma, strong analogies exist in terms of wave spectrum scalings and magnetic-field dependent dispersionless wave velocities.
Review
Physics, Fluids & Plasmas
Michael Berhanu
Summary: This article discusses the characteristics of gravity-capillary waves in laboratory and field conditions, the impact of viscous dissipation on nonlinear effects, and the conditions for nonlinear wave interactions and wave turbulence to occur.
