Physical Review E
Control of Rayleigh-Taylor instability onset time and convective velocity by differential diffusion effects
Author(s): S. S. Gopalakrishnan, J. Carballido-Landeira, B. Knaepen, and A. De Wit
Fingering instabilities of a miscible interface between two fluids in a gravitational field can develop due to adverse density gradients as in the well-known Rayleigh-Taylor (RT) and double-diffusive (DD) instabilities. In the absence of differential diffusion, the mixing rate and the onset time of ...
[Phys. Rev. E 98, 011101(R)] Published Tue Jul 17, 2018
Author(s): Soroush Aramideh, Pavlos P. Vlachos, and Arezoo M. Ardekani
Flow in porous media is known to be largely affected by pore morphology. In this work, we investigate the effects of pore geometry on the transport and spatial correlations of flow through porous media in two distinct pore structures arising from three-dimensional assemblies of overlapping and nonov...
[Phys. Rev. E 98, 013104] Published Fri Jul 13, 2018
Author(s): Arjang Shahriari, Preston S. Wilson, and Vaibhav Bahadur
At high temperatures, a droplet can rest on a cushion of its vapor (the Leidenfrost effect). Application of an electric field across the vapor gap fundamentally eliminates the Leidenfrost state by attracting liquid towards the surface. This study uses acoustic signature tracking to study electrostat...
[Phys. Rev. E 98, 013103] Published Thu Jul 12, 2018
Author(s): Hussein N. Dalgamoni and Xin Yong
Droplet-solid interaction is a ubiquitous fluid phenomenon that underpins a wide range of applications. To further the understanding of this important problem, we use an axisymmetric lattice Boltzmann method (LBM) to model the droplet impact on a solid surface with different wettability. The method ...
[Phys. Rev. E 98, 013102] Published Mon Jul 09, 2018
Controlling wetting with electrolytic solutions: Phase-field simulations of a droplet-conductor system
Author(s): Gaute Linga, Asger Bolet, and Joachim Mathiesen
The wetting properties of immiscible two-phase systems are crucial in applications ranging from laboratory-on-a-chip devices to field-scale oil recovery. It has long been known that effective wetting properties can be altered by the application of an electric field; a phenomenon coined as electrowet...
[Phys. Rev. E 98, 013101] Published Thu Jul 05, 2018
Author(s): Christopher Nilsen
We study the thermoviscous fingering instability problem that develops when an injected fluid is displacing a fluid with different temperature and viscosity in a Hele-Shaw cell or porous medium. Using linear stability theory, we show how the thermal front caused by the different temperature of the i...
[Phys. Rev. E 97, 063112] Published Fri Jun 29, 2018
Author(s): Ö. D. Gürcan
A nested polyhedra model has been developed for magnetohydrodynamic turbulence. Driving only the velocity field at large scales with random, divergence-free forcing results in a clear, stationary k−5/3 spectrum for both kinetic and magnetic energies. Since the model naturally effaces disparate scale...
[Phys. Rev. E 97, 063111] Published Tue Jun 26, 2018
Author(s): Kyle J. Caspary, Dahan Choi, Fatima Ebrahimi, Erik P. Gilson, Jeremy Goodman, and Hantao Ji
The effects of axial boundary conductivity on the formation and stability of a magnetized free Stewartson-Shercliff layer (SSL) in a short Taylor-Couette device are reported. As the axial field increases with insulating endcaps, hydrodynamic Kelvin-Helmholtz-type instabilities set in at the SSLs of ...
[Phys. Rev. E 97, 063110] Published Wed Jun 20, 2018
Author(s): Y. B. Sun, J. J. Tao, and X. T. He
In the previous studies of Rayleigh-Taylor instability, different methods were used to consider the effects of elasticity, viscosity, and magnetic fields. In this paper, a unified method, which was first used for fluids, is validated for different physical models, where the unstable mode is decompos...
[Phys. Rev. E 97, 063109] Published Tue Jun 19, 2018
Author(s): Kim M. J. Alards, Hadi Rajaei, Rudie P. J. Kunnen, Federico Toschi, and Herman J. H. Clercx
The angle of directional change of tracer trajectories in rotating Rayleigh-Bénard convection is studied as a function of the time increment τ between two instants of time along the trajectories, both experimentally and with direct numerical simulations. Our aim is to explore the geometrical charact...
[Phys. Rev. E 97, 063105] Published Mon Jun 18, 2018
Author(s): Binita Nath, Gautam Biswas, Amaresh Dalal, and Kirti Chandra Sahu
The present study focuses on the cross-stream migration of a neutrally buoyant two-dimensional drop in a Poiseuille flow in a channel under the influence of an electric field. In the absence of an electric field, the important nondimensional parameters describing this problem are the viscosity ratio...
[Phys. Rev. E 97, 063106] Published Mon Jun 18, 2018
Author(s): Aditya G. Nair, Steven L. Brunton, and Kunihiko Taira
A networked-oscillator-based analysis is performed to examine and control the transfer of kinetic energy for periodic bluff body flows. The dynamics of energy fluctuations in the flow field are described by a set of oscillators defined by conjugate pairs of spatial proper orthogonal decomposition (P...
[Phys. Rev. E 97, 063107] Published Mon Jun 18, 2018
Author(s): Egor Yushkov, Alexander Lukin, and Dmitry Sokoloff
We study average magnetic field growth in a mirror-symmetrical Kazantsev turbulent flow near the dissipative scales. Our main attention is directed to a subcritical regime, when an exponential decrease of magnetic energy is usually expected. We show that instead of damping, transient energy growth c...
[Phys. Rev. E 97, 063108] Published Mon Jun 18, 2018
Author(s): P. Bazazi, A. Sanati-Nezhad, and S. H. Hejazi
This paper reports the experimental results of a water droplet spreading on a glass substrate submerged in an oil phase. The radius of the wetted area grows exponentially over time forming two distinct regimes. The early time dynamics of wetting is characterized with the time exponent of 1, referred...
[Phys. Rev. E 97, 063104] Published Wed Jun 13, 2018
Author(s): Muralikrishnan Gopalakrishnan Meena, Aditya G. Nair, and Kunihiko Taira
A network community-based reduced-order model is developed to capture key interactions among coherent structures in high-dimensional unsteady vortical flows. The present approach is data-inspired and founded on network-theoretic techniques to identify important vortical communities that are comprise...
[Phys. Rev. E 97, 063103] Published Mon Jun 11, 2018
Author(s): Grégoire Bongrand and Peichun Amy Tsai
When a more mobile fluid displaces another immiscible one in a porous medium, viscous fingering propagates with a partial sweep, which hinders oil recovery and soil remedy. We experimentally investigate the feasibility of tuning such fingering propagation in a nonuniform narrow passage with a radial...
[Phys. Rev. E 97, 061101(R)] Published Fri Jun 08, 2018
Internal waves in sheared flows: Lower bound of the vorticity growth and propagation discontinuities in the parameter space
Author(s): Federico Fraternale, Loris Domenicale, Gigliola Staffilani, and Daniela Tordella
This study provides sufficient conditions for the temporal monotonic decay of enstrophy for two-dimensional perturbations traveling in the incompressible, viscous, plane Poiseuille, and Couette flows. Extension of Synge's procedure [J. L. Synge, Proc. Fifth Int. Congress Appl. Mech. 2, 326 (1938); S...
[Phys. Rev. E 97, 063102] Published Fri Jun 08, 2018
Author(s): Quoc Vo and Tuan Tran
Droplets on a surface immersed in oil are made to spread and retract by switching on and off a potential difference between the droplets and the surface. The authors find that the contact line friction depends on the viscosities of the droplet and the surrounding oil and that it does not depend significantly on the driving force or the direction of motion.
[Phys. Rev. E 97, 063101] Published Fri Jun 01, 2018
Author(s): V. Langlois, V. H. Trinh, C. Lusso, C. Perrot, X. Chateau, Y. Khidas, and O. Pitois
In this paper, we study how the permeability of solid foam is modified by the presence of membranes that close partially or totally the cell windows connecting neighboring pores. The finite element method (FEM) simulations computing the Stokes problem are performed at both pore and macroscopic scale...
[Phys. Rev. E 97, 053111] Published Thu May 31, 2018
Author(s): D. Veysset, U. Gutiérrez-Hernández, L. Dresselhaus-Cooper, F. De Colle, S. Kooi, K. A. Nelson, P. A. Quinto-Su, and T. Pezeril
In this study a single laser pulse spatially shaped into a ring is focused into a thin water layer, creating an annular cavitation bubble and cylindrical shock waves: an outer shock that diverges away from the excitation laser ring and an inner shock that focuses towards the center. A few nanosecond...
[Phys. Rev. E 97, 053112] Published Thu May 31, 2018