Article
Mechanics
Ilmars Grants
Summary: Different configurations of a rotating magnetic dipole-driven turbulent flow in an electrically conducting liquid cylinder were studied through numerical simulation and experiment, revealing that the orientation of the dipole can significantly affect the vortex formation, with secondary corner eddies increasing overall turbulent fluctuation when the magnetic dipole rotation vector is perpendicular to the cylinder's axis.
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
Mechanics
Ziyao Liu, Anthony J. C. Ladd
Summary: A rotating disk is a classic experiment for measuring surface reaction rates in geochemical and electrochemical systems. The study found that the flow becomes time dependent and there is non-uniform mass transfer in the flow around a finite-size disk.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Physics, Fluids & Plasmas
C. Jacques, B. Di Pierro, F. Alizard, M. Buffat, A. Cadiou, L. Le Penven
Summary: This paper addresses the linear stability problem of solid body rotating flows with axisymmetric density variations. Considering inviscid disturbances, a nontrivial dispersion relation is obtained, indicating that the instability is of Rayleigh-Taylor type in the cylindrical frame. The viscous correction is derived in the limit of large Reynolds numbers and large azimuthal wave numbers, enabling the determination of the most unstable mode. Theoretical predictions are verified by comparing them to computed eigenvalues and direct numerical simulations.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Mechanics
J. Sierra-Ausin, M. Lorite-Diez, J. I. Jimenez-Gonzalez, V. Citro, D. Fabre
Summary: This study examines the spatio-temporal pattern formation of wake flow past a streamwise rotating sphere from a dynamical system perspective. It reveals the connection between rotating waves and helical patterns within the wake. The research finds that, for low rotation rates, the flow field undergoes a transition similar to that of flow past a static sphere, but with a rapid variation in flow frequencies due to rotation. The transition from a single helix pattern to a double helix structure within the wake displays hysteric behavior in several regions. Eventually, the interaction between single and double helix structures leads to temporal chaos.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Geochemistry & Geophysics
Jacob Dafni, Joseph Wartman
Summary: This study used a geotechnical centrifuge experimental program to investigate topographic effects on single-sided slopes. The results showed that topography modified the frequency content and amplitude of ground motion, leading to significant changes in peak ground accelerations at the slope crest and determining the extent of the topographic zone of influence. The centrifuge proved to be a powerful experimental technique for systematically and repeatedly analyzing topographic effects.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2021)
Article
Mechanics
Manman Wang, Zhiye Zhao, Ankang Gao, Jiaxing Song, Nansheng Liu
Summary: The effects of rotation on turbulence in viscoelastic spanwise-rotating plane Couette flows were studied using direct numerical simulations at Re=1300 and Wi=5. Three regimes of rotation were identified: weak rotation, intermediate rotation, and strong rotation. Polymer-turbulence interactions were found to occur primarily in extensional flows at weak and intermediate rotation, and in the bulk region at high-Ro EIT state.
Article
Mechanics
Bartosz Protas, Stefan G. Llewellyn Smith, Takashi Sakajo
Summary: In this study, the rotating and translating equilibria of open finite vortex sheets in two-dimensional potential flows were considered, and new results were obtained regarding their stability. The linear instability of these equilibria was shown, with different growth characteristics of unstable perturbations in time. Interestingly, the stability results were obtained entirely through analytical computations, and comparisons were made with existing results for unbounded, periodic, and circular vortex sheets.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Mechanical
Nan Gao, Shiyu Wang, Jixiang Wang
Summary: This study examines the vibration characteristics of a thin ring subjected to internal and external excitations, and reveals that external excitations are the primary factor in changing vibration characteristics. By analyzing and classifying parameter combinations, the study identifies seven cases of parametric vibrations. Based on Floquet theory, the instability areas of multi-frequency excitations are obtained, and the impact of primary parameters on instabilities is studied. The study also uncovers the relationship between natural frequency splitting and parametric instability, and compares the findings with existing results in the literature.
NONLINEAR DYNAMICS
(2022)
Article
Mechanics
Antoine Faugaret, Yohann Duguet, Yann Fraigneau, Laurent Martin Witkowski
Summary: In this study, the contamination of an air-liquid interface by ambient pollutants in an experimental and numerical context was investigated. A simplified numerical model adaptable into any code for single-phase flows was proposed. The model's reliability was validated by comparing the results with experimental data.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Astronomy & Astrophysics
Shinsuke Takasao, Yuri Shuto, Keiichi Wada
Summary: This study investigates the magnetically driven outflows powered by a rotating, weakly magnetized accretion flow onto a supermassive black hole through axisymmetric magnetohydrodynamic simulations. The results show that a rotating disk formed on a parsec-scale acquires poloidal magnetic fields via accretion, leading to the formation of an asymmetric bipolar outflow. The growth of strongly magnetized regions around disk surfaces is found to be responsible for the formation of the outflow, which continuously grows inside expanding magnetic bubbles. The north-south asymmetrical structure of the bipolar outflow originates from the complex motions excited by accreting flows around the outer edge of the disk.
ASTROPHYSICAL JOURNAL
(2022)
Article
Engineering, Aerospace
Gustavo Castaneda Fuentes, Frank Huettmann, Sven Grundmann
Summary: Experiments were conducted in a towing tank to study the behavior of wake vortices after the landing of an aircraft. Different flow patterns in the wake vortex cores and their effects were observed, including wakelike and jetlike axial flows. The disturbances and their spatial-temporal behavior, including propagation velocities, were presented and discussed.
Article
Astronomy & Astrophysics
Subham Ghosh, Banibrata Mukhopadhyay
Summary: Research demonstrates that rotation stabilizes plane Couette flow, while destabilizing plane Poiseuille flow faster, leading to turbulence in forced local accretion disks.
ASTROPHYSICAL JOURNAL
(2021)
Article
Physics, Fluids & Plasmas
G. Varillon, J-M Clarisse, A. Couairon
Summary: The study reveals the possibility of fast transient growth of hydrodynamic perturbations in ablation flows relevant to inertial confinement fusion (ICF) due to nonmodal effects. Such growths, likely to arise in capsule ablators with material inhomogeneities, are too fast to be detected by existing measurement techniques and may lead to early transitions to nonlinear regimes. These findings call for a reconsideration of the stability of ICF flows within the framework of nonmodal stability theory.
Article
Mathematics, Applied
Eugen Magyari
Summary: The paper revisits three outstanding rotating disk flows described by an exact solution of the Navier-Stokes equations, aiming to investigate the mapping relationships between them. It is found that flow (A) is similar to flow (C), and can generate flow (B) through suitable scaling transformations, while flow (B) can generate a continuous set of solutions of flow (A).
ZAMM-ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK
(2021)
Correction
Astronomy & Astrophysics
David Cebron, Michael Le Bars, Patrice Le Gal, Claire Moutou, Jeremy Leconte, Alban Sauret
Correction
Mechanics
D. Cebron, M. Le Bars, J. Noir, J. M. Aurnou
Article
Astronomy & Astrophysics
Jeremie Vidal, David Cebron, Nathanael Schaeffer, Rainer Hollerbach
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2018)
Article
Geochemistry & Geophysics
D. Cebron, R. Laguerre, J. Noir, N. Schaeffer
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Astronomy & Astrophysics
J. Vidal, D. Cebron, A. Ud-Doula, E. Alecian
ASTRONOMY & ASTROPHYSICS
(2019)
Article
Geochemistry & Geophysics
R. Monville, J. Vidal, D. Cebron, N. Schaeffer
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Mechanics
Jeremie Vidal, Sylvie Su, David Cebron
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
Sylvie Su, David Cebron, Henri-Claude Nataf, Philippe Cardin, Jeremie Vidal, Max Solazzo, Yann Do
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2020)
Article
Multidisciplinary Sciences
Jeremie Vidal, David Cebron
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2020)
Article
Physics, Fluids & Plasmas
Deok-Hoon Jeong, Anezka Kvasnickova, Jean-Baptiste Boutin, David Cebron, Alban Sauret
PHYSICAL REVIEW FLUIDS
(2020)
Article
Mechanics
David Cebron, Jeremie Vidal, Nathanael Schaeffer, Antonin Borderies, Alban Sauret
Summary: The study investigates the generation mechanism of mean zonal flows in rapidly rotating fluid-filled spheroids, with theoretical predictions validated by numerical simulations. It further considers the impact of spatial and temporal perturbations, as well as spheroidal geometry on the zonal flows.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Jeremie Vidal, David Cebron
Summary: Motivated by the modeling of rotating turbulence in planetary fluid layers, this study investigates precession-driven flows in ellipsoids under stress-free boundary conditions. The results show that viscosity affects the long-term evolution of angular momentum in triaxial geometries and axisymmetric ellipsoids when the mean rotation axis of the fluid is not the symmetry axis. By using stress-free boundary conditions, the study also explores non-viscous instabilities that are relevant for planetary applications but are often limited in experiments or simulations that use no-slip boundary conditions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Physics, Applied
Nicolas Jaisle, David Cebron, Zuzana Konopkova, Rachel J. Husband, Clemens Prescher, Valerio Cerantola, Anand Dwivedi, Johannes M. Kaa, Karen Appel, Khachiwan Buakor, Orianna B. Ball, Ryan S. Mcwilliams, Cornelius Strohm, Motoaki Nakatsutsumi, Ulf Zastrau, Carsten Baehtz, Marzena Anna Baron, Eric Edmund, Joydipa Biswas, James D. Mchardy, Blake T. Sturtevant, Lars Ehm, Alexander F. Goncharov, Malcolm I. Mcmahon, Johannes Buchen, Hyunchae Cynn, Edward J. Pace, Hanns-Peter Liermann, Daniel T. Sneed, Samantha C. Cooper, Madison Anae, Jaeyong Kim, Zhongyan Wu, Yongjae Lee, Huijeong J. Hwang, Taehyun Kim, Jinhyuk Choi, Jeongmin Lee, Sebastien Merkel, Julien Chantel, Egor G. Koemets, Hauke Marquardt, Vitali B. Prakapenka, Stella Chariton, Elena Shevchenko, Guillaume Fiquet, Angelika D. Rosa, Mohamed Mezouar, Gaston Garbarino, Guillaume Morard
Summary: A new experimental approach combining pulsed laser heating with MHz x-ray diffraction has been implemented to determine liquidus temperatures under extreme conditions. This study focuses on a Fe-Si-O ternary system and uses a time-resolved diagnostic complemented by a finite-element model to reproduce temperature profiles. The model includes pressure and temperature dependencies as well as heat-induced thermal stress. The results show significant improvements compared to previous models, providing temperature, pressure, and volume conditions relevant to planetary cores.
JOURNAL OF APPLIED PHYSICS
(2023)
Correction
Mechanics
S. Vantieghem, D. Cebron, J. Noir
JOURNAL OF FLUID MECHANICS
(2017)
Review
Mechanics
Jeremie Vidal, David Cebron
JOURNAL OF FLUID MECHANICS
(2017)