Latest papers in fluid mechanics
Author(s): P. Debue, V. Shukla, D. Kuzzay, D. Faranda, E.-W. Saw, F. Daviaud, and B. Dubrulle
We examine the connection between the singularities or quasisingularities in the solutions of the incompressible Navier-Stokes equation (INSE) and the local energy transfer and dissipation, in order to explore in detail how the former contributes to the phenomenon of intermittency. We do so by analy...
[Phys. Rev. E 97, 053101] Published Thu May 03, 2018
Author(s): D. Fiscaletti and B. Ganapathisubramani
In turbulent boundary layers, the wall-normal gradient of the Reynolds shear stress identifies momentum sources and sinks. The spacetime evolution of these small-scale motions is experimentally investigated in a turbulent boundary layer with time-resolved particle image velocimetry.
[Phys. Rev. Fluids 3, 054601] Published Thu May 03, 2018
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): F. J. Uribe and R. M. Velasco
We use the Navier-Stokes-Fourier constitutive equations to study plane shock waves in dilute gases. It is shown that the experimental information on the normalized density profiles can be fit by using the so-called soft sphere model, in which the viscosity and thermal conductivity are proportional t...
[Phys. Rev. E 97, 043117] Published Mon Apr 30, 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): Cyril Pitrou
We build a general formalism to describe thin viscous jets as one-dimensional objects with an internal structure. We present in full generality the steps needed to describe the viscous jets around their central line, and we argue that the Taylor expansion of all fields around that line is convenient...
[Phys. Rev. E 97, 043115] Published Tue Apr 24, 2018
Author(s): Cyril Pitrou
In a companion paper [Phys. Rev. E 97, 043115 (2018)], a formalism allowing to describe viscous fibers as one-dimensional objects was developed. We apply it to the special case of a viscous fluid torus. This allows to highlight the differences with the basic viscous string model and with its viscous...
[Phys. Rev. E 97, 043116] Published Tue Apr 24, 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): Asger Bolet, Gaute Linga, and Joachim Mathiesen
In low-permeability rock, fluid and mineral transport occur in pores and fracture apertures at the scale of micrometers and below. At this scale, the presence of surface charge, and a resultant electrical double layer, may considerably alter transport properties. However, due to the inherent nonline...
[Phys. Rev. E 97, 043114] Published Mon Apr 23, 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
Discontinuous contact line motion of evaporating particle-laden droplet on superhydrophobic surfaces
Author(s): Yutaka Yamada and Akihiko Horibe
The three-phase contact line motion on a superhydrophobic surface through particle-laden sessile droplet evaporation was investigated. Sample surfaces with micro- and nanoscale structures were generated by various durations of chemical treatment and SiO2 spherical particles with different sizes were...
[Phys. Rev. E 97, 043113] 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