Physical Review Fluids
Author(s): Michiel A. J. van Limbeek, Paul B. J. Hoefnagels, Minori Shirota, Chao Sun, and Detlef Lohse
Reduction of the ambient pressure changes the boiling behavior of impacting ethanol drops on a heated substrate as observed by contact area measurements (insets). With decreasing ambient pressure, we find a widening of the transition boiling regime, while TLeidenfrost stays roughly constant.
[Phys. Rev. Fluids 3, 053601] Published Wed May 02, 2018
Author(s): Saúl Piedra, Joel Román, Aldo Figueroa, and Sergio Cuevas
In an experimental and numerical study, a magnet floating in a thin electrolyte layer is dragged and accelerated by a vortex dipole generated by a Lorentz force. Vortex shedding appears when a sufficiently high electric current is applied, promoting a zigzag magnet motion.
[Phys. Rev. Fluids 3, 043702] Published Mon Apr 30, 2018
Author(s): Galina E. Pavlovskaya, Thomas Meersmann, Chunyu Jin, and Sean P. Rigby
Magnetic resonance imaging is used to map out velocity fields during fluid flow in a clear channel coupled to a permeable wall. The maps are compared to lattice Boltzmann modeling to demonstrate that the velocity fields can be simulated without analytical expression of the boundary velocities.
[Phys. Rev. Fluids 3, 044102] Published Mon Apr 30, 2018
Hybrid finite-difference/lattice Boltzmann simulations of microchannel and nanochannel acoustic streaming driven by surface acoustic waves
Author(s): Ming K. Tan and Leslie Y. Yeo
The acoustic streaming flow in microchannels and nanochannels caused by complex fluid-structural coupling due to surface acoustic waves is studied using a hybrid continuum and mesoscale numerical model.
[Phys. Rev. Fluids 3, 044202] Published Mon Apr 30, 2018
Propulsion and maneuvering of an artificial microswimmer by two closely spaced waving elastic filaments
Author(s): Roei Elfasi, Yossef Elimelech, and Amir D. Gat
Hydrodynamic interaction between two adjacent waving elastic filaments is examined analytically and experimentally. Results show that antiphase beating is optimal for propulsion, hydrodynamic interaction modifies the optimal Sperm number, and phase difference between the filaments enables maneuvering.
[Phys. Rev. Fluids 3, 044203] Published Mon Apr 30, 2018
Author(s): Alexander Yelkhovsky and W. Val Pinczewski
Fluid inertia is usually ignored in network models used to predict flow in porous media. A model based on an averaged Navier-Stokes equation, validated for displacements in straight capillaries, is shown to capture the effects of inertia. Results suggest it can form the basis for more realistic network models.
[Phys. Rev. Fluids 3, 044003] Published Fri Apr 27, 2018
Author(s): Megan S. Davies Wykes, Jinzi Mac Huang, George A. Hajjar, and Leif Ristroph
Using candy “landforms” carved and reshaped by flowing water, laboratory experiments show how it is that some shapes keep a memory of earlier conditions as they develop while others forget the past, a fact that is important in geological dating and understanding how landscapes form.
[Phys. Rev. Fluids 3, 043801] Published Thu Apr 26, 2018
Author(s): Babak Nasouri and Gwynn J. Elfring
The effects of higher-order force moments of active particles on the flow field induced by their motion are investigated. Using the reciprocal theorem, explicit expressions for the stresslet dipole, rotlet dipole, and potential dipole of an arbitrarily shaped active particle are provided.
[Phys. Rev. Fluids 3, 044101] Published Wed Apr 25, 2018
Direct numerical simulation of flow over dissimilar, randomly distributed roughness elements: A systematic study on the effect of surface morphology on turbulence
Author(s): Pourya Forooghi, Alexander Stroh, Philipp Schlatter, and Bettina Frohnapfel
Direct numerical simulations of flow over fourteen dense rough walls with varying geometry are conducted. The effect of a departure from same-size element roughness on turbulence statistics is studied, and the correlation of the roughness function with wall-normal fluctuations at the roughness crest is examined.
[Phys. Rev. Fluids 3, 044605] Published Wed Apr 25, 2018
Author(s): Kourosh Shoele and Patrick S. Eastham
The swimming efficiency of an idealized microswimmer is theoretically examined where the pointwise viscosity depends weakly on the surrounding nutrient. Results show that optimal swimming efficiency is achieved differently in the constant- and variable-viscosity cases.
[Phys. Rev. Fluids 3, 043101] Published Tue Apr 24, 2018
Author(s): Z. M. Nikolaou, R. S. Cant, and L. Vervisch
A novel approach for modeling the scalar flux term in turbulent flames is presented. An iterative algorithm is used for “deblurring” the filtered field. Successive iterations lead to improved approximations of the original field, and explicit filtering is then used for modeling the scalar flux.
[Phys. Rev. Fluids 3, 043201] Published Mon Apr 23, 2018
Investigation of the Klinkenberg effect in a micro/nanoporous medium by direct simulation Monte Carlo method
Author(s): Guang Yang and Bernhard Weigand
We define effective pore size as a function of the porosity, the tortuosity, the contraction factor, and the intrinsic permeability of the porous medium. The Klinkenberg effect in different porous structures is found to be fully described by the Knudsen number characterized by this pore size.
[Phys. Rev. Fluids 3, 044201] Published Fri Apr 20, 2018
Author(s): Ruslan Khalilov, Ilya Kolesnichenko, Alexander Pavlinov, Andrey Mamykin, Alexander Shestakov, and Peter Frick
The effect of inclination on the sodium (Pr=0.0094) turbulent convection in a cylinder of unit aspect ratio was studied experimentally for a fixed Rayleigh number Ra=(1.47±0.03)×107, and the inclination angle varied from 0° (the Rayleigh-Benard convection) up to 90° with a step of 10°.
[Phys. Rev. Fluids 3, 043503] Published Fri Apr 20, 2018
Experimental and numerical investigation of electrohydrodynamic flow in a point-to-ring corona discharge
Author(s): Yifei Guan, Ravi Sankar Vaddi, Alberto Aliseda, and Igor Novosselov
An electrohydrodynamic flow in a point-to-ring corona configuration is investigated experimentally and numerically. A parameter X, defined as the ratio of the local electric force to the inertial term, characterizes the effect of electrohydrodynamic forcing on bulk flow.
[Phys. Rev. Fluids 3, 043701] Published Fri Apr 20, 2018
Minimal formulation of the linear spatial analysis of capillary jets: Validity of the two-mode approach
Author(s): H. González, P. A. Vazquez, F. J. García, and J. Guerrero
Linear models are often used for the evolution of capillary jets. Here we present the simplest linear spatial formulation and compare it to numerical simulations. Two magnitudes, shape deformation, and mean axial velocity, and two spatial modes are needed, with one of them decaying exponentially.
[Phys. Rev. Fluids 3, 044802] Published Wed Apr 18, 2018
Fingering patterns in magnetic fluids: Perturbative solutions and the stability of exact stationary shapes
Author(s): Pedro H. A. Anjos, Sérgio A. Lira, and José A. Miranda
Pattern formation processes in magnetic fluids confined in a Hele-Shaw cell and subjected to a radial magnetic field are studied. It is shown that the weakly nonlinear flow drives an initially circular interface towards nontrivial exact stationary shapes, which are dynamically stable.
[Phys. Rev. Fluids 3, 044002] Published Tue Apr 17, 2018
Author(s): C.-H. Bruneau, P. Fischer, Y.-L. Xiong, and H. Kellay (Cyclobulle Collaboration)
Original numerical simulations of 2D turbulent convection on a hemisphere are presented. Nusselt and Reynolds numbers verify scaling laws consistent with Rayleigh-Bénard convection. Despite significant differences in geometry with classical 3D cells, the scaling laws of thermal convection are robust.
[Phys. Rev. Fluids 3, 043502] Published Mon Apr 16, 2018
Author(s): Christian Wischnewski and Jan Kierfeld
The numerical and analytical investigation of elastic capsules filled with a ferrofluid/dielectric liquid in a uniform magnetic/electric field shows a discontinuous spherical-to-conical shape transition for increasing fields with diverging strains in the conical tips.
[Phys. Rev. Fluids 3, 043603] Published Mon Apr 16, 2018
Author(s): Yaqing Jin, Jin-Tae Kim, and Leonardo P. Chamorro
The interaction between wall-mounted, flexible plates and wake fluctuations is experimentally investigated as a function of several geometrical and flow parameters. It is demonstrated that significant decoupling between the dynamics of the structures and flow may occur because of near-wake flow instability.
[Phys. Rev. Fluids 3, 044701] Published Fri Apr 13, 2018
Author(s): Dhrubaditya Mitra and Prasad Perlekar
In a study of inertial particle velocity gradients and the corresponding flow topology, the density weighted joint distribution shows that converging saddle structures are most probable.
[Phys. Rev. Fluids 3, 044303] Published Thu Apr 12, 2018