Article
Astronomy & Astrophysics
Maria Fedotova, Dmitry Klimachkov, Arakel Petrosyan
Summary: Increased interest in research of non-linear resonant interactions of waves in rotating astrophysical plasma has been seen recently, especially with the discovery of solar magneto-Rossby waves and new data on three-wave interactions of magneto-Rossby waves affecting solar activity. The study highlights magneto-Poincare waves and magneto-Rossby waves in the context of large-scale magnetohydrodynamic flows with rotation, using the beta-plane approximation to simplify the theory of spherical Rossby waves. Analysis of complete dispersion equations on the beta-plane reveals new dispersion relations for magneto-Poincare waves and uncovers new types of three-wave interactions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Mechanics
F. Garcia, A. Giesecke, F. Stefani
Summary: This study explores the triadic resonances in the magnetized spherical Couette system and their relationship with the development of modulated rotating waves. Through frequency analysis of different flow modes, it reveals the nonlinear coupling among resonant modes. The research proposes a general framework for generating triadic resonances through Hopf bifurcations from the base state.
Article
Mechanics
J. Sanchez Umbria, M. Net
Summary: The aim of this study is to investigate the three-dimensional torsional dynamics of thermal convection in rotating spherical fluids at very low Prandtl numbers through numerical simulations. The study shows that the breaking of axisymmetry at a secondary Hopf bifurcation leads to a quasiperiodic motion that propagates energy in both latitude and longitude, resulting in a meandering path of kinetic energy concentrated on the surface. Different stable states of convection with various symmetries have been identified, all retaining the torsional motion of the basic velocity field, with attention paid to their dependence on Rayleigh number and other factors.
Article
Mechanics
Geert Brethouwer
Summary: The study shows that rotation can significantly influence passive tracer transport in shear flows, making it much faster than momentum transport, in violation of the Reynolds analogy. This dissimilarity is observed in steady flows with large counter-rotating vortices at low Reynolds numbers as well as in fully turbulent flows at higher Reynolds numbers. The Coriolis force induced by rotation dampens velocity fluctuations more strongly than tracer fluctuations near the neutral stability limit, breaking the Reynolds analogy.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Geert Brethouwer
Summary: Rotation has a significant impact on flows and transport processes in engineering applications, but its effects are not fully understood. In this study, numerical simulations are used to investigate the influence of rotation on heat and momentum transfer in Couette and Taylor-Couette flows. It is found that anti-cyclonic rotation initially increases the Nusselt numbers for momentum and heat transfer, but they decrease and approach unity at high rotation rates. The Reynolds analogy factor also increases with rotation, indicating that the heat transfer can become faster than momentum transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Mechanics
Mohammed Hussein Hamede, Sebastian Merbold, Christoph Egbers
Summary: This experiment studies the turbulent Taylor-Couette flow between two concentric independently rotating cylinders with a radius ratio of 0.1. The flow patterns are observed to depend on the rotation ratio, showing a more pronounced axial dependence. The angular momentum transport is calculated using recorded flow fields and exhibits a maximum for low counter-rotating cases. The space-time behavior of the turbulent flow reveals patterns propagating from both the inner and outer regions, enhancing the angular momentum transport.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Nathan Paldor, David G. Dritschel
Summary: The study examines the late-time evolution of an inviscid zonally symmetric shallow-water flow on the surface of a rotating spherical earth and compares it to the simpler problem of uniformly rotating shallow-water flow on a plane. Despite waves on a sphere unable to propagate to infinity, a form of adjustment still takes place in a time-averaged sense, similar to geostrophic balance in the planar case.
Article
Physics, Fluids & Plasmas
J. Sanchez Umbria, M. Net
Summary: The aim of this work is to investigate the transitions that occur when periodic axisymmetric flows lose stability in rotating fluid spheres, and to study the behavior of new stable velocity fields until the flows become temporally chaotic. The computations show that as the Prandtl number decreases, the stability range of these flows becomes narrower due to the rapid increase in kinetic energy of the axisymmetric periodic solutions, favoring their instability. The stability analysis and simulations reveal that the transition to stable quasiperiodic flows through Neimark-Sacker bifurcations is supercritical when Pr ≤ 0.01. For Pr = 0.1, two branches of stable periodic flows are found emerging from the conduction state due to the proximity to a double Hopf bifurcation. However, only the branches bifurcating from the azimuthal rotating waves remain stable at large Rayleigh numbers. Far from this bifurcation, the stable flows retain the influence of the axisymmetric dynamics until large Rayleigh numbers. For small Pr, they exhibit repeated transients of mixed dynamics controlled by the azimuthal wave numbers m = 0, m = 1, and m = 2.
Article
Thermodynamics
Obaidullah Khawar, M. F. Baig, Sanjeev Sanghi
Summary: The present work investigates counter-rotating turbulent Taylor-Couette flows with a radial temperature gradient and examines the influence of Reynolds number and Richardson number on flow statistics, flow dynamics, and near-wall coherent structures.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2022)
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
Astronomy & Astrophysics
J. R. Canivete Cuissa, R. Teyssier
Summary: This study conducted three-dimensional numerical simulations of magneto-hydrodynamics in stellar interiors and demonstrated the feasibility of the simulation method. The results showed an exponential growth of magnetic energy and a decrease in power of acoustic and internal gravity waves. The study highlights the importance of including magnetic fields in the study of pressure waves.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Mechanics
Yufeng Lin, Andrew Jackson
Summary: This study focuses on the dynamics of Boussinesq convection in a rotating full sphere, particularly on the development of large-scale coherent structures and mean zonal flows. The research reveals the critical role of the convective Rossby number in the formation and transition of large-scale vortices.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Karthikeyan Jagadeesan, Vagesh D. Narasimhamurthy, Helge I. Andersson
Summary: This study revisits the direct numerical simulation (DNS) of rib-roughened turbulent channel flow rotating about its spanwise axis. The combined effects of roughness and Coriolis force on turbulence were analyzed. The results showed that rotation caused preferential aligning of near-wall vortical structures and the rotational production rates played a significant role in distributing kinetic energy. The structure of turbulence was significantly affected by rotation.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2022)
Article
Multidisciplinary Sciences
T. F. Flint, M. C. Smith, P. Shanthraj
Summary: This study presents a new formulation of the time-dependent magnetic induction equation coupled with conservation laws for multi-phase fluid flow, energy transport, and chemical species transport. The proposed novel projection method ensures divergence-free magnetic field. Validation is done by replicating Hartmann flow profile and predicting Argon bubble trajectory, as well as simulating an electrical arc welding process. The framework addresses the need for numerical methods in understanding multi-phase systems with large electromagnetic property contrast.
SCIENTIFIC REPORTS
(2021)
Review
Astronomy & Astrophysics
Maria Fedotova, Dmitry Klimachkov, Arakel Petrosyan
Summary: This article introduces different models and reviews the latest magnetohydrodynamic theories of wave processes in rotating astrophysical plasma, considering important and common properties of astrophysical objects such as compressibility and stratification. It fills the gap in theoretical studies in the field of plasma astrophysics and contributes to improving numerical modeling schemes efficiency.
Article
Geochemistry & Geophysics
M. Lasbleis, R. Deguen, P. Cardin, S. Labrosse
GEOPHYSICAL JOURNAL INTERNATIONAL
(2015)
Article
Geosciences, Multidisciplinary
A. Lincot, S. Merkel, P. Cardin
GEOPHYSICAL RESEARCH LETTERS
(2015)
Correction
Physics, Multidisciplinary
Simon Cabanes, Nathanael Schaeffer, Henri-Claude Nataf
PHYSICAL REVIEW LETTERS
(2015)
Article
Geosciences, Multidisciplinary
A. Lincot, Ph. Cardin, R. Deguen, S. Merkel
GEOPHYSICAL RESEARCH LETTERS
(2016)
Article
Mechanics
Celine Guervilly, Philippe Cardin
JOURNAL OF FLUID MECHANICS
(2016)
Article
Geochemistry & Geophysics
C. Guervilly, P. Cardin
GEOPHYSICAL JOURNAL INTERNATIONAL
(2017)
Article
Geochemistry & Geophysics
N. Schaeffer, D. Jault, H. -C. Nataf, A. Fournier
GEOPHYSICAL JOURNAL INTERNATIONAL
(2017)
Article
Physics, Multidisciplinary
E. J. Kaplan, N. Schaeffer, J. Vidal, P. Cardin
PHYSICAL REVIEW LETTERS
(2017)
Article
Physics, Fluids & Plasmas
E. J. Kaplan, H. -C. Nataf, N. Schaeffer
PHYSICAL REVIEW FLUIDS
(2018)
Editorial Material
Geosciences, Multidisciplinary
Philippe Cardin, Sebastien Merkel
COMPTES RENDUS GEOSCIENCE
(2014)
Article
Geochemistry & Geophysics
Z. Tigrine, H. -C. Nataf, N. Schaeffer, P. Cardin, F. Plunian
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Multidisciplinary Sciences
Celine Guervilly, Philippe Cardin, Nathanael Schaeffer
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
Astronomy & Astrophysics
Henri-Claude Nataf
Summary: The idea of a planetary origin for the solar cycle has a long history and some researchers still advocate for it. Recently, a scenario based on this idea was proposed, with the key argument being evidence of the rhythmic nature of the approximately 11-year solar cycle. However, the assumptions and time series used in the demonstration may render it invalid. Additionally, instabilities in a magnetized fluid can also produce fluctuation time series that exhibit clock-like behavior.
Article
Mechanics
Essam Nabil Ahmed, Alessandro Bottaro
Summary: This study focuses on the fully developed, steady, incompressible, laminar flow in a channel with rough and/or permeable walls. The influence of micro-structured boundary surfaces on the flow behavior is simulated using high-order effective boundary conditions derived from homogenization theory without empirical parameters. A closed-form solution of the Navier-Stokes equations is obtained for the flow in the channel, incorporating slip velocities, shear stress, and streamwise pressure gradient at each virtual boundary. The accuracy and applicability of the model are validated against full feature-resolving simulations for different textures. The Stokes-based model used to identify slip and interface permeability coefficients in the effective boundary conditions is reliable and accurate up to a certain threshold, beyond which advective effects need to be considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Mustafa Turkyilmazoglu, Faisal Z. Duraihem
Summary: Thermally-driven natural convection in a porous layer is explored theoretically in this work based on Darcy's law. The study focuses on the non-circulating basic cellular flow between two infinitely long horizontal plates and its instability onset. The results show that a circulatory flow and temperature variation along the horizontal axis govern the motion, and the instability can be determined through linear stability analysis and numerical calculations.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
P. Roca Ramis de Ayreflor, A. Viudez
Summary: In this study, the inelastic interactions between a small, intense dipole and a weak, neutral monopole in two-dimensional flows are examined. It is found that dipoles with small size but large amplitude can cross and scatter off the neutral vortex, while leaving the vortex stable.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Nilanjan Mondal, Chirodeep Bakli
Summary: This study presents a micro-nanochannel junction with directional flow achieved by a combination of junction geometry and wall functionalization. The system acts as a fluid diode with asymmetric pressure drop and flow rate in the nanochannel. The directional junction transport can be tuned with slip length, providing a key parameter for engineering various applications. The findings contribute to the understanding of flow rectification systems in nanochannels and have implications for capillary blood flow, desalination systems, and energy storage devices.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Ussama Ali, Anas Ghannam, Md Islam, Isam Janajreh
Summary: This study utilizes a passive flow control technique involving a slit through a circular structure to dampen flow-induced vibration. The results demonstrate that the presence of a slit can decrease lift and drag coefficients and suppress flow-induced vibration.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sebastian A. Altmeyer
Summary: This article investigates how an alternating magnetic field can restrict and suppress the generation of vortices in ferrofluidic Couette flow. It finds that when the initially rotating outer cylinder is suddenly stopped, more complex vortex dynamics are generated in the system, and the presence of an alternating magnetic field can modify these dynamics, mainly depending on the modulation amplitude of the field.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Pradeep, L. P. Singh
Summary: This study focuses on the analytical solution to the Riemann problem for a 1-D non-ideal flow of dusty gas with external force. The elementary wave curves, including rarefaction wave, shock wave, and contact discontinuity, were obtained and their implications on density, velocity of flow, and shock speed were examined. The addition of external force results in non-self-similar solutions.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Meng Fan, Antoine Dazin, Gerard Bois, Francesco Romano
Summary: This study investigates the prominent features of the primary instabilities of a turbulent source flow between finite-span parallel rings with spatially modulated inflow conditions rotating at angular rate n. Two different two-dimensional instabilities that occur at large and low flow rates have been traced back to two different physical mechanisms related to jet-wake and mean-core flow, respectively. The effect of the radial aspect ratios on the instability characteristics of the flow between parallel rings is also considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Yasmin Hengster, Martin Lellep, Julian Weigel, Matthew Bross, Johannes Bosbach, Daniel Schanz, Andreas Schroder, Florian Huhn, Matteo Novara, Daniel Garaboa Paz, Christian J. Kahler, Moritz Linkmann
Summary: Using curvature and torsion to describe Lagrangian trajectories provides insights into small and large time scales. Probability density functions (PDFs) of curvature and torsion were calculated for experimental Lagrangian trajectories in different flows, and were compared with experimental and numerical simulation results. The effect of anisotropy on geometry or tracer particle trajectories was quantified using the curvature vector, which was found to be related to velocity fluctuations.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Nang X. Ho, Truong V. Vu
Summary: The present paper reports numerical results on the solidification process of a hollow drop on an inclined surface. The drop undergoes deformation and forms an asymmetric tip as the surface angle increases. The solidification time, however, is not affected by the surface angle. The fluid accumulates at the bottom of the drop and the bubble moves upwards before being trapped by solidification. A larger bubble reduces the tip shift. The effect of Bond number and Stefan number on solidification is also considered.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Idalia Jagodzinska, Bartosz Olszanski, Konrad Gumowski, Slawomir Kubacki
Summary: This study investigates the characteristics of high subsonic and transonic flows through a linear cascade using experimental investigations and numerical simulations. The experiments measured static pressure, flow field, and turbulent intensity, and provided inlet conditions for the numerical simulations. The simulations validated the experimental data and tested the applicability of the turbulence models.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Kun Sung Park, Ali Zamiri, Minsuk Choi, Byung Ju Lee, Jin Taek Chung
Summary: In this study, the stator geometry of a single-stage transonic fan was optimized to improve its aerodynamic performance and stall margin. Steady and unsteady simulations were conducted to analyze the impact of shock waves generated by the rotor blade on the stator inlet flow. Using a design of experiment and response surface method, an optimal geometry of the stator blade was obtained to increase the fan's efficiency and stall margin.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Yuanzhao Zhang, Bo Li
Summary: This study investigated the effects of longitudinal and lateral spacing on the aerodynamic drag characteristics of the whole team and each member in speed skating team pursuit competition. The results showed that decreasing the longitudinal spacing resulted in greater drag reduction for the whole team and individual skaters. Furthermore, lateral movement of the leading skater also led to additional drag reduction for the team. Computational fluid dynamics simulations revealed differences in drag distribution between the leading skater and the middle and last skaters.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sichang Xu, Chris Peirone, Eugene Ryzer, Gary W. Rankin
Summary: This paper presents a study of a special bistable load-type supersonic fluidic oscillator capable of producing self-sustained oscillations in two gas pressure chambers. The experimental portion verifies the robust nature of the device performance and shows distinct differences compared to a similar prototype. A three-dimensional computational fluid dynamics model is required to accurately simulate the transient filling process, leading to an unaffordable computational cost. To address this issue, a low-order fluid circuit model is developed, which provides an accurate and rapid prediction of the transient performance.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
Article
Mechanics
Sampson Davis, Eli Shellabarger, James Miller, Thomas Ward
Summary: The present work focuses on studying the effects of shock wave - boundary layer interaction in 2D hypersonic flow at the sharp leading edge of a flat plate and a flat plate followed by a compression ramp. A key parameter, the hypersonic interaction parameter x, is defined and analyzed using a semi-analytic reduced-order model. The study aims to improve on existing methods by characterizing the viscous boundary layer and investigating the upstream influence resulting from the compression ramp.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2024)
