Article
Mechanics
Masato Nagata, Baofang Song, Darren P. Wall
Summary: The study reveals the presence of tilted-vortex flow and periodic-vortex flow at the onset of instability in rotating plane Couette flow, challenging the previously established understanding of bifurcations at the transition from laminar to turbulent flow.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Engineering, Multidisciplinary
Soumya Mukherjee, D. Giribabu
Summary: This paper conducts a linear stability analysis on the impact of initially stressed solid in fluid flow, finding that initial tensile stress stabilizes the flow while compressive stress destabilizes it, which is related to the stability of solid structures.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2021)
Article
Mathematics
Luqi Wang, Zhifei Zhang, Hao Zhu
Summary: In this paper, the researchers investigate the stationary structures near the planar Couette flow and the asymptotic behavior of Couette flow for the beta-plane equation. By determining the boundaries between different regions, they conclude that the existence of non-shear traveling waves depends on specific conditions. This contrasting dynamics plays a significant role in studying the long time dynamics of Couette flow with Coriolis effects.
ADVANCES IN MATHEMATICS
(2023)
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
Physics, Fluids & Plasmas
Mathi Raja, Adrian van Kan, Benjamin Foster, Edgar Knobloch
Summary: This article studies the order parameter description of several convective systems with reflection symmetry, uses numerical continuation and direct numerical simulations to study the effects of breaking symmetry in the cubic-quintic Swift-Hohenberg equation, and investigates collision scenarios and the resulting final states of traveling structures. The stability properties of bound states and the interactions between structures are analyzed, and a reduced model is proposed to capture the dynamics of the system.
Article
Mechanics
T. Kawata, T. Tsukahara
Summary: Nonlinear interactions between different scales in turbulence play an important role in the transport of turbulent energy and the heat transfer mechanism. This study investigates the interactions between scales in velocity and temperature fields in a turbulent plane Couette flow with passive-scalar heat transfer. The results show that turbulent heat transfer occurs at smaller length scales compared to momentum transfer, and the scale interactions in the temperature field supply more energy to small scales. The significant temperature cascade leads to more energetic temperature fluctuation at small scales, resulting in spectral dissimilarity between turbulent heat and momentum transfers. Published under an exclusive license by AIP Publishing.
Article
Mechanics
Toni Dokoza, Martin Oberlack
Summary: In direct numerical simulations (DNS) of turbulent Couette flow, it has been observed that the length of long streamwise rolls increases with the Reynolds number. To understand this phenomenon, both linear stability theory and resolvent analysis are employed under the high Reynolds number (Re ≥ 8) and small streamwise wavenumbers (a ≥ 0) limit. The study reveals that the streamwise wavenumber of the structures needs to decrease to obtain constant streamwise structures with increasing Reynolds numbers, confirming the observations from DNS studies.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mathematics, Applied
Xuan Ma, Yating Wang
Summary: In this paper, the dynamics of a rarefied gas in a finite channel is studied, specifically focusing on the phenomenon of Couette flow. The authors demonstrate that the unsteady Couette flow for the Boltzmann equation converges to a 1D steady state and derive the exponential time decay rate. The analysis holds for all hard potentials.
NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
(2024)
Article
Thermodynamics
A. Barletta, M. Celli, S. Lazzari, P. V. Brandao
Summary: This study examines mixed convection flow in a plane channel with adiabatic boundaries. The externally prescribed relative velocity of the boundaries creates a Couette-like flow setup. The flow regime is stationary with a constant velocity difference between the thermally insulated boundaries. Viscous dissipation leads to a heat source and a temperature gradient in the flow domain, causing a combined forced and free flow regime.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Review
Multidisciplinary Sciences
Jiaxing Song, Yabiao Zhu, Fenghui Lin, Nansheng Liu, Bamin Khomami
Summary: This retrospective aims to present a coherent history of important findings in direct numerical simulations and experiments in turbulent Taylor-Couette flow of dilute polymeric solutions in the last decade. Specifically, the article discusses the sequence of flow transitions due to an increase in fluid elasticity, including drag modification, flow structures, statistics, and mechanisms of turbulence, as well as a comparison with curvilinear and rectilinear shear flows. This article is part of a theme issue on Taylor-Couette and related flows.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Multidisciplinary Sciences
Masato Nagata
Summary: A Cartesian representation of the Taylor-Couette system in the vanishing limit of the gap between cylinders is presented, showing the influence of the angular velocities ratio on the axisymmetric flow structures. Numerical stability study confirms previous findings on the critical Taylor number for the onset of axisymmetric instability. Additionally, the mean flow distortion of the axisymmetric flow exhibits symmetric or antisymmetric distribution across the gap depending on the value of the angular velocities ratio.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Mechanics
Vishal Panwar, Athena E. Metaxas, Cari S. Dutcher
Summary: Research has shown that changes in polymer chain conformation can affect the stability and flow characteristics of TC flow, with increasing solution ionic strength leading to a more Newtonian behavior of the fluid. The study also observed the effects of co-rotation and counter-rotation of the cylinders on the stability of flow states, with co-rotation stabilizing some polymer-influenced flow states and counter-rotation destabilizing flow states.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2021)
Article
Thermodynamics
Yun Kyung Choi, Jae Hwa Lee, Jinyul Hwang
Summary: Direct numerical simulations of a turbulent Couette-Poiseuille flow with zero-mean-shear at the moving wall show significantly elongated logarithmic region, larger Reynolds stresses in both inner and outer layers, increased number of uniform momentum zones, and importance of outer layer structures in the turbulent energy transfer process.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2021)
Article
Mechanics
Yue Xiao, Jianjun Tao, Linsen Zhang
Summary: In this study, it is demonstrated that the convection velocity of a localized wave packet in two-dimensional plane-Poiseuille flow is determined by the solitary wave at the centerline of a vortex dipole. The fluctuation component propagates following the local dispersion relation of the mean flow and oscillates with a global frequency selected by the upstream marginal absolute instability, making it a traveling wave mode. The vortex dipole creates an unstable region for the fluctuation waves to grow, with the Reynolds stress of the fluctuation waves enhancing the vortex dipole.
Article
Mechanics
M. Manna, A. Vacca, R. Verzicco
Summary: Direct numerical simulations were performed to analyze the reverse transition dynamics of a turbulent spiral Poiseuille flow in a narrow-gap geometry at low Taylor number. It was found that a complete laminarization occurred at a significantly lower Reynolds number compared to the non-rotating case. The differences in the reverse transition process between the spiral Poiseuille flow and plain Poiseuille flow were attributed to the modifications of the isotropy of the Reynolds stress tensor, caused by changes in the velocity pressure-strain redistribution mechanisms.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Multidisciplinary Sciences
Florian Reetz, Tobias Kreilos, Tobias M. Schneider
NATURE COMMUNICATIONS
(2019)
Article
Mechanics
Sajjad Azimi, Tobias M. Schneider
JOURNAL OF FLUID MECHANICS
(2020)
Article
Multidisciplinary Sciences
Yaouen Fily, Priya Subramanian, Tobias M. Schneider, Raghunath Chelakkot, Arvind Gopinath
JOURNAL OF THE ROYAL SOCIETY INTERFACE
(2020)
Article
Mechanics
Florian Reetz, Tobias M. Schneider
JOURNAL OF FLUID MECHANICS
(2020)
Article
Mechanics
Florian Reetz, Priya Subramanian, Tobias M. Schneider
JOURNAL OF FLUID MECHANICS
(2020)
Article
Physics, Fluids & Plasmas
Simon S. Schuetz, Jian Wei Khor, Sindy K. Y. Tang, Tobias M. Schneider
PHYSICAL REVIEW FLUIDS
(2020)
Article
Physics, Multidisciplinary
Anais Abramian, Emmanuel Virot, Emilio Lozano, Shmuel M. Rubinstein, Tobias M. Schneider
PHYSICAL REVIEW LETTERS
(2020)
Article
Mechanics
Sajjad Azimi, Tobias M. Schneider
Summary: The study investigates the impact of symmetry breaking on the three-dimensional plane Couette flow homoclinic snaking, revealing that wall-normal suction can modify the bifurcation structure of solutions. This modification disrupts the connected snakes-and-ladders structure and leads to the creation of previously unknown solution branches.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Physics, Fluids & Plasmas
Florian Reetz, Tobias M. Schneider
Summary: Transitional plane Couette flow can exhibit regular turbulent-laminar stripe patterns with large-scale pattern wavelength and an oblique orientation relative to the laminar flow direction due to spatiotemporally chaotic dynamics. An analysis of the Navier-Stokes equations shows unstable equilibrium solutions capturing the spatial structure of the oblique stripe patterns. Unstable periodic orbits embedded in the symmetry subspace of plane Couette flow may mediate the transition between turbulent flows with oblique patterns and laminar flow.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mechanics
J. P. Parker, T. M. Schneider
Summary: This article proposes a family of methods to converge unstable periodic orbits for the incompressible Navier-Stokes equations. The methods are based on variations of an integral objective functional and traditional gradient-based optimization strategies. The variational methods are applied to a specific case of two-dimensional Kolmogorov flow and compared with existing Newton iteration-based shooting methods. The methods are computationally slow but able to converge from inaccurate initial guesses.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mathematics, Applied
Jeremy P. P. Parker, Tobias M. M. Schneider
Summary: One method to comprehend the chaotic dynamics of nonlinear dissipative systems is through the exploration of non-chaotic yet dynamically unstable invariant solutions, including fixed points, one-dimensional unstable periodic orbits, and two-dimensional unstable invariant tori. This study demonstrates the generic existence of unstable 2-tori in a dissipative system of ordinary differential equations, which can be numerically identified and characterized. These higher-dimensional tori, together with periodic orbits and equilibria, form a complete set of relevant invariant solutions for understanding chaos.
Article
Physics, Fluids & Plasmas
Sajjad Azimi, Omid Ashtari, Tobias M. Schneider
Summary: This study proposes a matrix-free method for computing periodic orbits in high-dimensional spatiotemporal chaotic systems. The method is globally convergent and unaffected by exponential error amplification. Experimental results demonstrate the robustness and convergence of the method.
Article
Physics, Fluids & Plasmas
John M. Kolinski, Tobias M. Schneider
Summary: Research suggests that SARS-CoV-2 may be transmitted through the air, with analysis of superspreading events indicating a single virion exposure value and the plausibility of aerosol transmission.
Article
Physics, Fluids & Plasmas
Matthew Salewski, John F. Gibson, Tobias M. Schneider
Article
Biochemical Research Methods
Simon S. Schutz, Thomas Beneyton, Jean-Christophe Baret, Tobias M. Schneider
