Transient-time correlation function applied to mixed shear and elongational flows
Remco Hartkamp, Stefano Bernardi, and B. D. Todd
The transient-time correlation function (TTCF) method is used to calculate the nonlinear response of a homogeneous atomic fluid close to equilibrium. The TTCF response of the pressure tensor subjected to a time-independent planar mixed flow of shear and elongation is compared to directly averaged no ... [J. Chem. Phys. 136, 064105 (2012)] published Fri Feb 10, 2012.
Intrinsic Stability of a Body Hovering in an Oscillating Airflow
Bin Liu, Leif Ristroph, Annie Weathers, Stephen Childress, and Jun Zhang
We explore the stability of flapping flight in a model system that consists of a pyramid-shaped object hovering in a vertically oscillating airflow. Such a flyer not only generates sufficient aerodynamic force to keep aloft but also robustly maintains balance during free flight. Flow visualization r ... [Phys. Rev. Lett. 108, 068103 ] published .
Oscillatory bubbles induced by geometrical constraint
M. Pailha, A. L. Hazel, P. A. Glendinning, and A. Juel
We show that a simple change in pore geometry can radically alter the behavior of a fluid-displacing air finger, indicating that models based on idealized pore geometries fail to capture key features of complex practical flows. In particular, partial occlusion of a rectangular cross section can forc ... [Phys. Fluids 24, 021702 (2012)] published Thu Feb 9, 2012.
Carbon nanotube-coated silicated soft magnetic carbonyl iron microspheres and their magnetorheology
Y. D. Liu and H. J. Choi
Core-shell structured magnetic microspheres were fabricated by coating the surface of silicated soft magnetic carbonyl iron particles with multi-walled carbon nanotubes using a facile layer-by-layer method involving an alternative sequential adsorption of positive and negative polyelectrolytes. The ... [J. Appl. Phys. 111, 07B502 (2012)] published Thu Feb 9, 2012.
Immiscible displacement of oil by water in a microchannel: Asymmetric flow behavior and nonlinear stability analysis of core-annular flow
Hooman Foroughi, Alireza Abbasi, Kausik S. Das, and Masahiro Kawaji
The immiscible displacement of oil by water in a circular microchannel was investigated. A fused silica microchannel with an inner diameter of 250 [mu]m and a length of 7 cm was initially filled with a viscous silicone oil. Only water then was injected into the channel. We describe our flow observat ... [Phys. Rev. E 85, 026309 ] published .
Direct numerical simulation of two-dimensional wall-bounded turbulent flows from receptivity stage
T. K. Sengupta, S. Bhaumik, and Y. G. Bhumkar
Deterministic route to turbulence creation in 2D wall boundary layer is shown here by solving full Navier-Stokes equation by dispersion relation preserving (DRP) numerical methods for flow over a flat plate excited by wall and free stream excitations. Present results show the transition caused by wa ... [Phys. Rev. E 85, 026308 ] published .
Pseudocompressible approximation and statistical turbulence modeling: Application to shock tube flows
Olivier Soulard, Jerome Griffond, and Denis Souffland
In this work, a pseudocompressible approximation relevant for turbulent mixing flows encountered in shock tubes is derived. The asymptotic analysis used for this purpose puts forward the role played by four dimensionless numbers on the flow compressibility, namely, the turbulent, deformation, strati ... [Phys. Rev. E 85, 026307 ] published .
Secondary instability in the near-wake past two tandem square cylinders
Choon-Bum Choi, Yong-Jun Jang, and Kyung-Soo Yang
Floquet stability analysis has been carried out to detect the onset of the secondary instability in the laminar flow past two identical square cylinders in tandem. Presence of a neighbouring cylinder alters flow topology, leading to change of stability characteristics. A parametric study has been pe ... [Phys. Fluids 24, 024102 (2012)] published Wed Feb 8, 2012.
Parametric study of cylindrical converging shock waves generated based on shock dynamics theory
Zhigang Zhai, Ting Si, Xisheng Luo, Jiming Yang, Cangli Liu et al.
In our previous work, the technique of generating cylindrical converging shock waves based on shock dynamics theory was proposed. In the present work, a further study is carried out to assess the influence of several parameters including the converging angle theta, the incident planar shock Mach num ... [Phys. Fluids 24, 026101 (2012)] published Wed Feb 8, 2012.
Observation of collision and oscillation of microdroplets with extremely large shear deformation
Tatsuya Yamada and Keiji Sakai
We measured the viscosity and surface tension of various liquids under large (~10 s) shear deformation. Oscillation of a 10-[mu]m size microdroplet is brought about by the head-on collision of two droplets. Since the Reynolds number is as small as 100, the motion of the liquid is stable and the dyna ... [Phys. Fluids 24, 022103 (2012)] published Wed Feb 8, 2012.
Thermal boundary layer profiles in turbulent Rayleigh-Benard convection in a cylindrical sample
Richard J. A. M. Stevens, Quan Zhou, Siegfried Grossmann, Roberto Verzicco, Ke-Qing Xia et al.
We numerically investigate the structures of the near-plate temperature profiles close to the bottom and top plates of turbulent Rayleigh-Benard flow in a cylindrical sample at Rayleigh numbers Ra=10 to Ra=2 x 10 and Prandtl numbers Pr=6.4 and Pr=0.7 with the dynamical frame method [Zhou and Xia, Ph ... [Phys. Rev. E 85, 027301 ] published .
Stability of double-diffusive double-convective miscible displacements in porous media
J. Azaiez and M. Sajjadi
The present study offers a paradigm on the stability of two-component miscible displacements in a homogeneous porous medium. The components have, in general, different mobility ratios, may diffuse at different rates, and are convected at different speeds. As a result, one of the components may lag b ... [Phys. Rev. E 85, 026306 ] published .
Extension of the momentum transfer model to time-dependent pipe turbulence
Esteban Calzetta
We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows [Phys. Rev. Lett. 96, 044502 (2006)] to the case of time- and/or space-dependent turbulent flows. The end result is an expression for the stress at the wall as the sum of a s ... [Phys. Rev. E 85, 026305 ] published .
Thermocapillary motion of a slender viscous droplet in a channel
E. Katz, M. Haj, A. M. Leshansky, and A. Nepomnyashchy
We extend the previously developed low-capillary-number asymptotic theory of thermocapillary motion of a long bubble and a moderately viscous droplet in a channel [S. K. Wilson, The effect of an axial temperature gradient on the steady motion of a large droplet in a tube, J. Eng. Math. 29, 205 (1995 ... [Phys. Fluids 24, 022102 (2012)] published Tue Feb 7, 2012.
Fluid flows in a librating cylinder
Alban Sauret, David Cebron, Michael Le Bars, and Stephane Le Dizes
The flow in a cylinder driven by time-harmonic oscillations of the rotation rate, called longitudinal librations, is investigated. Using a theoretical approach and axisymmetric numerical simulations, we study two distinct phenomena appearing in this librating flow. First, we investigate the occurren ... [Phys. Fluids 24, 026603 (2012)] published Tue Feb 7, 2012.
Study of instabilities and transitions for a family of quasi-two-dimensional magnetohydrodynamic flows based on a parametrical model
S. Smolentsev, N. Vetcha, and R. Moreau
In this study, flow phenomena associated with inflectional and boundary-layer instabilities, as well as a mixed instability mode in quasi-two-dimensional magnetohydrodynamic flows in a rectangular duct are accessed with the help of a parametrical model, where the basic velocity profile with near-wal ... [Phys. Fluids 24, 024101 (2012)] published Tue Feb 7, 2012.
Strain-vorticity induced secondary motion in shallow flows
Leon P. J. Kamp
Deviations from two-dimensionality of a shallow flow that is dominated by bottom friction are quantified in terms of the spatial distribution of strain and vorticity as described by the Okubo-Weiss function. This result is based on a Poisson equation for the pressure in a quasi-horizontal (primary) ... [Phys. Fluids 24, 023601 (2012)] published Mon Feb 6, 2012.
Effects of particles on stability of flow-induced precursors
Peng-Wei Zhu, Andrew W. Phillips, and Graham Edward
The effect of two colorant particles with different surface geometries on the stability of shear-induced precursors in isotactic polypropylene was studied after the cessation of shear flow at 140 degrees C. In the absence of particles, the shear-induced precursors survived for at least 100 s after ... [J. Chem. Phys. 136, 054903 (2012)] published Mon Feb 6, 2012.
Mobility matrix of a spherical particle translating and rotating in a viscous fluid confined in a spherical cell, and the rate of escape from the cell
B. U. Felderhof and A. Sellier
The mobility matrix of a spherical particle moving in a spherical cavity, filled with a viscous incompressible fluid, and with no-slip boundary condition at the wall of the cavity, is evaluated from the Oseen tensor for the cavity by the method used by Lorentz for a particle near a planar wall. For ... [J. Chem. Phys. 136, 054703 (2012)] published Mon Feb 6, 2012.
Discrete Salt Crystallization at the Surface of a Porous Medium
S. Veran-Tissoires, M. Marcoux, and M. Prat
Efflorescence refers to crystallized salt structures that form at the surface of a porous medium. The challenge is to understand why these structures do not form everywhere at the surface of the porous medium but at some specific locations and why there exists an exclusion distance around an efflore ... [Phys. Rev. Lett. 108, 054502 ] published .
Magnetic field amplification by small-scale dynamo action: Dependence on turbulence models and Reynolds and Prandtl numbers
Jennifer Schober, Dominik Schleicher, Christoph Federrath, Ralf Klessen, and Robi Banerjee
The small-scale dynamo is a process by which turbulent kinetic energy is converted into magnetic energy, and thus it is expected to depend crucially on the nature of the turbulence. In this paper, we present a model for the small-scale dynamo that takes into account the slope of the turbulent veloci ... [Phys. Rev. E 85, 026303 ] published .
Breakup of small aggregates driven by turbulent hydrodynamical stress
Matthaus U. Babler, Luca Biferale, and Alessandra S. Lanotte
The breakup of small solid aggregates in homogeneous and isotropic turbulence is studied theoretically and by using direct numerical simulations at high Reynolds number, Re~=400. We show that turbulent fluctuations of the hydrodynamic stress along the aggregate trajectory play a key role in determin ... [Phys. Rev. E 85, 025301 ] published .
Relating statistics to dynamics in axisymmetric homogeneous turbulence. (arXiv:1202.1970v1 [physics.flu-dyn])
ePrint arXiv http://arXiv.org/
Hamiltonian description and traveling waves of the spatial Dysthe equations. (arXiv:1110.3605v2 [physics.class-ph] CROSS LISTED)
ePrint arXiv http://arXiv.org/