Latest papers in fluid mechanics
Author(s): Katherine E. Witt, S. Farzad Ahmadi, and Jonathan B. Boreyko
We observe silicone oils wicking across dendritic sheets of frost. The capillary action is found to be dependent upon both the surface orientation and the underlying surface wettability.
[Phys. Rev. Fluids 4, 024002] Published Fri Feb 08, 2019
Author(s): Sagar Zade, Walter Fornari, Fredrik Lundell, and Luca Brandt
Many large spherical particles that sediment and resuspend from the bottom of a duct under fully developed turbulent conditions are studied. Optical experiments and direct numerical simulations are compared and used to investigate turbulence modulation and organization of particles.
[Phys. Rev. Fluids 4, 024303] Published Fri Feb 08, 2019
Author(s): Jonathan Poggie and Kevin M. Porter
High-fidelity simulations show that the confining effect of sidewalls on a shock-wave/boundary-layer interaction can have a very strong influence on both the mean flow and large-scale unsteadiness, and accurately capturing the sidewall flows is essential in realistic modeling of confined flows.
[Phys. Rev. Fluids 4, 024602] Published Fri Feb 08, 2019
Author(s): Jingtao Ma, Lincheng Xu, Fang-Bao Tian, John Young, and Joseph C. S. Lai
The dynamic characteristics of a two-dimensional deformable capsule in a simple shear flow are studied with an immersed boundary-lattice Boltzmann method. Simulations are conducted by varying the Reynolds number (Re) from 0.0125 to 2000 and the dimensionless shear rate (G) from 0.001 to 0.5. The G-R...
[Phys. Rev. E 99, 023101] Published Thu Feb 07, 2019
Author(s): X. M. Zhai, K. R. Sreenivasan, and P. K. Yeung
Small-scale characteristics of turbulence such as velocity gradients and vorticity fluctuate rapidly in magnitude and oscillate in sign. Much work exists on the characterization of magnitude variations, but far less on sign oscillations. While in homogeneous turbulence averages performed on large sc...
[Phys. Rev. E 99, 023102] Published Thu Feb 07, 2019
Characterizing vortex tangle properties in steady-state He II counterflow using particle tracking velocimetry
Author(s): Brian Mastracci and Wei Guo
The utility of particle tracking velocimetry for characterizing the quantized vortex tangle in He II thermal counterflow is shown by demonstrating measurements of vortex line spacing, the parameter c2, and vortex reconnection.
[Phys. Rev. Fluids 4, 023301] Published Thu Feb 07, 2019
Application of a self-organizing map to identify the turbulent-boundary-layer interface in a transitional flow
Author(s): Zhao Wu, Jin Lee, Charles Meneveau, and Tamer Zaki
We use the self-organizing map, an unsupervised machine learning method, to find the turbulent/nonturbulent interface in a transitional boundary layer with the help of Johns Hopkins Turbulence Databases. This method separates turbulent regions from vortical streaks and free-stream turbulence.
[Phys. Rev. Fluids 4, 023902] Published Thu Feb 07, 2019
Author(s): Patrick M. Seiler, Mark Gloerfeld, Ilia V. Roisman, and Cameron Tropea
The motion of wall-bounded drops moving on solid substrates driven by a fully turbulent channel flow is experimentally investigated. A scaling is found to describe the dimensionless drop velocity in terms of a dimensionless flow attack velocity, taking into account the surface wetting properties.
[Phys. Rev. Fluids 4, 024001] Published Thu Feb 07, 2019
Author(s): P. McGavin and D. I. Pontin
Reconnection of vortex tubes containing twisted vortex lines is studied by numerical simulation, showing that both the sense and strength of the twist affect the topological and geometrical properties of the resulting vortex structures, as well as the timing and rate of the reconnection process.
[Phys. Rev. Fluids 4, 024701] Published Thu Feb 07, 2019
Author(s): Francesco Romanò, Parvathy Kunchi Kannan, and Hendrik C. Kuhlmann
Finite-size Lagrangian coherent structures can arise in dilute suspensions solely because of the size of the particles. When moving near boundaries, a lubrication-induced drag transfers the particles from the chaotic sea of the unperturbed fluid flow to particular Kolmogorov-Arnold-Moser tori.
[Phys. Rev. Fluids 4, 024302] Published Wed Feb 06, 2019
Fast, thin jets from bubbles expanding and collapsing in extreme vicinity to a solid boundary: A numerical study
Author(s): Christiane Lechner, Werner Lauterborn, Max Koch, and Robert Mettin
Numerical solutions of the compressible Navier-Stokes equation for a bubble collapsing close to a solid boundary find a very thin jet with velocities of 1000m/s.
[Phys. Rev. Fluids 4, 021601(R)] Published Tue Feb 05, 2019
Author(s): John M. Lawson, Eberhard Bodenschatz, Anna N. Knutsen, James R. Dawson, and Nicholas A. Worth
Using 3D averages of energy dissipation rather than a surrogate quantity, high-resolution volumetric measurements and numerical simulations show that velocity increments scale with the local dissipation rate as per Kolmogorov’s 1962 refined similarity hypothesis, supporting small-scale universality.
[Phys. Rev. Fluids 4, 022601(R)] Published Tue Feb 05, 2019
Author(s): Itzhak Fouxon and Yizhar Or
We study inertial spherical squirmers prescribing tangential surface deformations. Breaking axial symmetry induces rotation-translation coupling that overcomes the “scallop theorem”, giving net motion for time-reversible strokes. This swimming mechanism may be relevant for large Volvox colonies.
[Phys. Rev. Fluids 4, 023101] Published Tue Feb 05, 2019
Temperature fluctuations relevant to thermal-plume dynamics in turbulent rotating Rayleigh-Bénard convection
Author(s): Shan-Shan Ding, Hui-Min Li, Wen-Dan Yan, and Jin-Qiang Zhong
Experiments in turbulent rotating Rayleigh-Bénard convection find various statistical properties of the fluctuations of the temperature which can be fit with a model.
[Phys. Rev. Fluids 4, 023501] Published Mon Feb 04, 2019
Author(s): S. Bharathraj and V. Kumaran
A simulation study of a dense granular inclined plane flow reveals a sharp transition between a Bagnold flow and a layered flow at critical angle, which is a fraction of a degree above the cessation angle. The layered flow exhibits intriguing features, such as oscillations of the flow velocity.
[Phys. Rev. Fluids 4, 024301] Published Mon Feb 04, 2019
Author(s): Wei Ran, Armin Zare, M. J. Philipp Hack, and Mihailo R. Jovanović
Multimodal stability analysis and parabolization are combined to account for dominant mode interactions in pretransitional flow. A sequence of linear progressions of the resulting parabolized Floquet equations captures disturbance growth and provides excellent agreement with direct numerical simulation results.
[Phys. Rev. Fluids 4, 023901] Published Fri Feb 01, 2019
Three-wave resonant interactions and zonal flows in two-dimensional Rossby-Haurwitz wave turbulence on a rotating sphere
Author(s): Kiori Obuse and Michio Yamada
The importance of zonal modes in discussing three-wave resonant nonlinear interactions in two-dimensional turbulence on a rotating sphere is investigated. Zonal modes should not be ignored although the energy exchanges between zonal and nonzonal modes by resonant interactions are not possible.
[Phys. Rev. Fluids 4, 024601] Published Fri Feb 01, 2019