POF: Letters and Brief Communications http://scitation.aip.org/ POF: Letters and Brief Communications Oscillatory bubbles induced by geometrical constraint http://link.aip.org/link/?PHF/24/021702/1&agg=rss M. Pailha, A. L. Hazel, P. A. Glendinning, and A. Juel<br/> 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. Re-examining the logarithmic dependence of the mean velocity distribution in polymer drag reduced wall-bounded flow http://link.aip.org/link/?PHF/24/021701/1&agg=rss C. M. White, Y. Dubief, and J. Klewicki<br/> A re-examination of the logarithmic dependence of the mean velocity distribution in polymer drag reduced flows shows that drag reducing polymers modify the von Karman coefficient and, in channel flow, eradicate the log-layer at high drag reductions. It is also found that the ultimate profile, corres ... [Phys. Fluids 24, 021701 (2012)] published Fri Feb 3, 2012. An analogy of Taylor's instability criterion in Couette and rotating-magnetic-field-driven flows http://link.aip.org/link/?PHF/24/011704/1&agg=rss Marius Ungarish<br/> The classical stability solution of Taylor for the Couette flow between a rotating inner cylinder and a stationary outer cylinder is used to model the critical magnetic Taylor number, Ta, in a flow of a liquid metal driven by a rotating magnetic field (RMF) in a cylindrical cavity characterized by t ... [Phys. Fluids 24, 011704 (2012)] published Wed Jan 11, 2012. Amplification factors in shock-turbulence interactions: Effect of shock thickness http://link.aip.org/link/?PHF/24/011705/1&agg=rss Diego A. Donzis<br/> Amplification factors of streamwise velocity are investigated in canonical shock-turbulence interactions. The ratio of laminar shock thickness to the Kolmogorov length scale is suggested as the appropriate parameter to understand data from simulations and experiments. The different regimes of the in ... [Phys. Fluids 24, 011705 (2012)] published Wed Jan 11, 2012. Direct simulation Monte Carlo method for an arbitrary intermolecular potential http://link.aip.org/link/?PHF/24/011703/1&agg=rss Felix Sharipov and Jose L. Strapasson<br/> A scheme to implement an arbitrary intermolecular potential into the direct simulation Monte Carlo method is proposed. To illustrate the scheme, two benchmark problems are solved employing the Lennard-Jones potential. Since the computational effort of the new scheme is comparable with that of the ha ... [Phys. Fluids 24, 011703 (2012)] published Mon Jan 9, 2012. Grid-point requirements for large eddy simulation: Chapman's estimates revisited http://link.aip.org/link/?PHF/24/011702/1&agg=rss Haecheon Choi and Parviz Moin<br/> Resolution requirements for large eddy simulation (LES), estimated by Chapman [AIAA J. 17, 1293 (1979)], are modified using accurate formulae for high Reynolds number boundary layer flow. The new estimates indicate that the number of grid points (N) required for wall-modeled LES is proportional to R ... [Phys. Fluids 24, 011702 (2012)] published Fri Jan 6, 2012. The onset of oblique vortex shedding behind a heated circular cylinder in laminar wake regime http://link.aip.org/link/?PHF/24/011701/1&agg=rss Ming-Hsun Wu, Zdenak TravniCek, and An-Bang Wang<br/> Oblique vortex shedding (OVS) behind a heated circular cylinder in air was experimentally investigated. Similar to that in the parallel vortex shedding (PVS), the results show that the non-dimensionalized shedding frequency, Strouhal number, decreases under the influence of cylinder heating for obli ... [Phys. Fluids 24, 011701 (2012)] published Thu Jan 5, 2012. The relationship between the velocity skewness and the amplitude modulation of the small scale by the large scale in turbulent boundary layers http://link.aip.org/link/?PHF/23/121702/1&agg=rss Romain Mathis, Ivan Marusic, Nicholas Hutchins, and K. R. Sreenivasan<br/> A defining feature of the inner-outer interactions in wall-bounded turbulent flows is the imprint of the outer large-scale motions on the inner small scale. Recently, Mathis et al. [Large-scale amplitude modulation of the small-scale structures in turbulent boundary layers, J. Fluid Mech. 628, 311 ( ... [Phys. Fluids 23, 121702 (2011)] published Fri Dec 23, 2011. Effect of spanwise confinement on flag flutter: Experimental measurements http://link.aip.org/link/?PHF/23/111704/1&agg=rss Olivier Doare, David Mano, and Juan Carlos Bilbao Ludena<br/> The effect of spanwise clearance on the critical velocity for fluttering of a cantilevered plate in a channel flow is addressed experimentally. It is found that the critical velocity is influenced by the presence of the walls when the ratio between the clearance and the length of the plate C/L is le ... [Phys. Fluids 23, 111704 (2011)] published Tue Nov 29, 2011. Three-dimensionalization of the stratified mixing layer at high Reynolds number http://link.aip.org/link/?PHF/23/111701/1&agg=rss A. Mashayek and W. R. Peltier<br/> Numerical analyses of the stability of a stratified two-dimensional Kelvin-Helmholtz billow against three dimensional disturbances provide a theoretical means of identifying the primary mechanism(s) that induce transition to turbulence. We identify, through fully resolved three-dimensional numerical ... [Phys. Fluids 23, 111701 (2011)] published Thu Nov 17, 2011. Orientational order in concentrated suspensions of spherical microswimmers http://link.aip.org/link/?PHF/23/111702/1&agg=rss Arthur A. Evans, Takuji Ishikawa, Takami Yamaguchi, and Eric Lauga<br/> We use numerical simulations to probe the dynamics of concentrated suspensions of spherical microswimmers interacting hydrodynamically. Previous work in the dilute limit predicted orientational instabilities of aligned suspensions for both pusher and puller swimmers, which we confirm computationally ... [Phys. Fluids 23, 111702 (2011)] published Thu Nov 17, 2011. Stability of steady flow through an axially corrugated pipe http://link.aip.org/link/?PHF/23/111703/1&agg=rss S. A. Loh and H. M. Blackburn<br/> The linear stability of steady flow in pipes with circular cross-section and sinusoidal axial variation in diameter is studied by finding global eigenmodes with axial wavelength commensurate with that of the wall corrugation, chosen to be equal to one pipe mean radius. The maximum peak-to-peak heigh ... [Phys. Fluids 23, 111703 (2011)] published Thu Nov 17, 2011. Lagrangian time correlations of vorticity alignments in isotropic turbulence: Observations and model predictions http://link.aip.org/link/?PHF/23/101704/1&agg=rss Laurent Chevillard and Charles Meneveau<br/> Motivated by results from recent particle tracking experiments in turbulence Xu et al. [Nature Phys. 7, 709 (2011)], we study the Lagrangian time correlations of vorticity alignments with the three eigenvectors of the deformation-rate tensor. We use data from direct numerical simulations (DNS), and ... [Phys. Fluids 23, 101704 (2011)] published Mon Oct 31, 2011. An apparent symmetry property of the mean velocity gradient in turbulent Poiseuille flows and its implications http://link.aip.org/link/?PHF/23/101705/1&agg=rss F. Laadhari<br/> A novel feature of the mean velocity gradient in turbulent parallel Poiseuille flows has been found using the results available in databases of direct numerical simulations at moderately high friction Reynolds number R, up to 2000. The computed turbulence statistics show that the logarithm of the me ... [Phys. Fluids 23, 101705 (2011)] published Mon Oct 31, 2011. Negative turbulent production during flow reversal in a stratified oscillating boundary layer on a sloping bottom http://link.aip.org/link/?PHF/23/101703/1&agg=rss Bishakhdatta Gayen and Sutanu Sarkar<br/> Three-dimensional direct numerical simulations are performed to model an internal tidal beam at near-critical slope, and the phase dependence of turbulent processes is investigated. Convective instability leads to density overturns that originate in the upper flank of the beam and span the beam widt ... [Phys. Fluids 23, 101703 (2011)] published Wed Oct 19, 2011. Confined shocks inside isolated liquid volumes: A new path of erosion? http://link.aip.org/link/?PHF/23/101702/1&agg=rss D. Obreschkow, N. Dorsaz, P. Kobel, A. de Bosset, M. Tinguely et al.<br/> The unique confinement of shock waves inside isolated liquid volumes amplifies the density of shockliquid interactions. We investigate this universal principle through an interdisciplinary study of shock-induced cavitation inside liquid volumes, isolated in 2 and 3 dimensions. By combining high-spee ... [Phys. Fluids 23, 101702 (2011)] published Thu Oct 13, 2011. Drag reduction of a hairy disk http://link.aip.org/link/?PHF/23/101701/1&agg=rss Jun Niu and David L. Hu<br/> We investigate experimentally the hydrodynamics of a hairy disk immersed in a two-dimensional flowing soap film. Drag force is measured as a function of hair length, density, and coating area. An optimum combination of these parameters yields a drag reduction of 17%, which confirms previous numerica ... [Phys. Fluids 23, 101701 (2011)] published Mon Oct 10, 2011. The destabilization of an initially thick liquid sheet edge http://link.aip.org/link/?PHF/23/091705/1&agg=rss Henri Lhuissier and Emmanuel Villermaux<br/> By forcing the sudden dewetting of a free soap film attached on one edge to a straight solid wire, we study the recession and subsequent destabilization of its free edge. The newly formed rim bordering the sheet is initially thicker than the film to which it is attached, because of the Plateau borde ... [Phys. Fluids 23, 091705 (2011)] published Fri Sep 30, 2011. Kolmogorov similarity scaling for one-particle Lagrangian statistics http://link.aip.org/link/?PHF/23/091704/1&agg=rss Brian L. Sawford and P. K. Yeung<br/> We use direct numerical simulation data up to a Taylor scale Reynolds number R = 1000 to investigate Kolmogorov similarity scaling in the inertial sub-range for one-particle Lagrangian statistics. Although similarity scaling is not achieved at these Reynolds numbers for the Lagrangian velocity struc ... [Phys. Fluids 23, 091704 (2011)] published Fri Sep 30, 2011. Frictional slip lengths and blockage coefficients http://link.aip.org/link/?PHF/23/091703/1&agg=rss Darren Crowdy<br/> This paper shows that the frictional slip lengths for longitudinal Stokes shear flow over a superhydrophobic surface are precisely the blockage coefficients for uniform potential flow past screens with the same geometry. This observation facilitates useful knowledge transfer between two apparently d ... [Phys. Fluids 23, 091703 (2011)] published Wed Sep 28, 2011. On the spectra of nozzle-exit velocity disturbances in initially nominally turbulent, transitional jets http://link.aip.org/link/?PHF/23/091702/1&agg=rss Christophe Bogey, Olivier Marsden, and Christophe Bailly<br/> In a recent paper by C. Bogey, O. Marsden, and C. Bailly [Large-eddy simulation of the flow and acoustic fields of a Reynolds number 10 subsonic jet with tripped exit boundary layers, Phys. Fluids 23(3), 035104 (2011)], simulation results were presented for round jets with tripped boundary layers, d ... [Phys. Fluids 23, 091702 (2011)] published Mon Sep 26, 2011.