Latest papers in fluid mechanics
Author(s): Alexandros Charogiannis, Fabian Denner, Berend G. M. van Wachem, Serafim Kalliadasis, Benoit Scheid, and Christos N. Markides
Space/time-resolved film-thickness data are presented for liquid films flowing under an inverted planar substrate. Different flow regimes are observed depending on the inclination, liquid properties, and Reynolds number, with waves characterized by pronounced three-dimensionality and rivulet formation.
[Phys. Rev. Fluids 3, 114002] Published Fri Nov 09, 2018
Author(s): J. Yuan and M. Aghaei Jouybari
Current understanding of turbulence in the vicinity of surface roughness is mostly limited to narrow-scale or regular roughness geometries. A numerical analysis shows how various scales of a multiscale, realistic roughness affect friction, momentum balance, and turbulence production in the roughness sublayer.
[Phys. Rev. Fluids 3, 114603] Published Fri Nov 09, 2018
Author(s): Jason Reneuve, Julien Salort, and Laurent Chevillard
A nonlocal version of the Gross-Pitaevskii equation is investigated. The role of rotons in vortex reconnection is probed through numerical simulations of both local (standard) and nonlocal models. Observed dynamics are compared with the predictions of the local induction approximation.
[Phys. Rev. Fluids 3, 114602] Published Thu Nov 08, 2018
Characteristics of turbulent boundary layer large scale motions using direct fluctuating wall shear stress measurements
Author(s): Rommel J. Pabon, Lawrence Ukeiley, Mark Sheplak, and Casey Barnard Keane
A microelectromechanical-systems-based floating element wall-shear-stress sensor (1×1 mm) is validated in a turbulent boundary layer for its ability to measure characteristics of large-scale motions.
[Phys. Rev. Fluids 3, 114604] Published Thu Nov 08, 2018
Author(s): Seunghyun Cho, Jooha Kim, and Haecheon Choi
Longitudinal strips are suggested as a new device that can significantly increase the aerodynamic performance of a low Reynolds number airfoil at post-stall angles of attack. Its mechanism relies on the generation of corner vortices that delay flow separation on the airfoil suction surface.
[Phys. Rev. Fluids 3, 113901] Published Wed Nov 07, 2018
Axial and radial patterns of a bidispersed suspension in a fully filled horizontal rotating cylinder
Author(s): John C. Nasaba and Anugrah Singh
We report on the pattern formation in a horizontal rotating cylinder fully filled with bidispersed suspension composed of non-Brownian settling and floating particles. The effect of particle mixing of different buoyancy and shape on the axial and radial pattern formation was investigated using flow ...
[Phys. Rev. E 98, 053102] Published Tue Nov 06, 2018
Lean premixed reacting flows with swirl and wall-separation zones in a contracting open circular chamber
Author(s): Zvi Rusak, Yuxin Zhang, Jung J. Choi, and Shixiao Wang
A model problem of low-Mach number lean premixed reacting swirling flows with wall-separation zones in a contracting open chamber is studied. A theoretical feasibility for a technology of swirl-assisted combustion where the reaction zone is supported by a wall-separation zone is established.
[Phys. Rev. Fluids 3, 113201] Published Tue Nov 06, 2018
Author(s): Gigi Lin, John M. Frostad, and Gerald G. Fuller
Thin-film experiments with an interferometric apparatus show an absence of a strong relationship between interfacial elasticity and liquid entrainment in thin foam films, which can affect rational design of aesthetic and tactile properties in foaming consumer products.
[Phys. Rev. Fluids 3, 114001] Published Tue Nov 06, 2018
Temperature gradient induced double stabilization of the evaporation front within a drying porous medium
Author(s): N. Vorhauer, E. Tsotsas, and M. Prat
The flow of water vapor against temperature gradients naturally occurring in drying of porous media leads to condensation and simultaneous gas-liquid invasion of pore space. This phenomenon is studied with a model porous medium in a microfluidic device and a pore network model of drying and imbibition.
[Phys. Rev. Fluids 3, 114201] Published Tue Nov 06, 2018
Author(s): D. Lunz and P. D. Howell
Motivated by plasma particles impacting a liquid-metal divertor, an analysis is performed to investigate how a liquid’s free surface is deflected by a moving applied pressure. It is found that the plasma can be swept up and down the liquid in order to spread the heat load, however, this may induce dangerously large deflections.
[Phys. Rev. Fluids 3, 114801] Published Tue Nov 06, 2018
Author(s): Mpumelelo Matse, Peter Berg, and Michael Eikerling
A theoretical model is developed that describes nonlinear coupling between wall deformation and water and ion flows in a charged, deformable nanochannel whose viscoelasticity is governed by the Kelvin-Voigt model. Using continuum mean-field theories for mass and momentum conservation of the solid-li...
[Phys. Rev. E 98, 053101] Published Thu Nov 01, 2018
Author(s): Robert H. Davis and Alexander Z. Zinchenko
Hydrophobic particles are selectively separated from aqueous suspension by a novel oil-in-water binder. The collection efficiency is predicted in this work by a hydrodynamic trajectory analysis, and shown to be greatly enhanced by water permeation through the oil layer.
[Phys. Rev. Fluids 3, 113601] Published Thu Nov 01, 2018
Author(s): Alexandros Alexakis
An investigation of how large-scale flow is affected by changes in the properties of small-scale flows, the layer thickness, and viscosity is presented.
[Phys. Rev. Fluids 3, 114601] Published Thu Nov 01, 2018
Author(s): Yogesh Jethani, Kamal Kumar, A. Sameen, and Manikandan Mathur
Local stability equations are solved along closed fluid particle trajectories in the cylinder wake for Reynolds numbers in the range of 50 to 300. A bifurcation is shown to occur at Re≈250 and is argued to be related to the emergence of the well-known mode-B secondary instability.
[Phys. Rev. Fluids 3, 103902] Published Wed Oct 31, 2018
Author(s): Linlin Fei, Andrea Scagliarini, Andrea Montessori, Marco Lauricella, Sauro Succi, and Kai H. Luo
We further develop a two-range pseudopotential Lattice Boltzmann method for soft flowing systems using tunable surface tension and viscosity ratio. It is applicable to multicomponent fluids with a viscosity-independent disjoining pressure, a key to the microfluidic design of new porous materials.
[Phys. Rev. Fluids 3, 104304] Published Wed Oct 31, 2018
Law of the wall for small-scale streamwise turbulence intensity in high-Reynolds-number turbulent boundary layers
Author(s): B. Ganapathisubramani
Following the dimensional analysis approach of previous works, a law-of-the-wall is proposed for small-scale fluctuations in turbulent wall-flow. Experimental data shows that this universal scaling law extends across almost the entire wall-layer and exhibits a logarithmic trend in the outer region.
[Phys. Rev. Fluids 3, 104607] Published Wed Oct 31, 2018
Author(s): Benjamin Marchetti, Veronica Raspa, Anke Lindner, Olivia du Roure, Laurence Bergougnoux, Élisabeth Guazzelli, and Camille Duprat
A flexible fiber settling in a viscous fluid deforms and reorients to adopt eventually a more or less pronounced “U” shape, regardless of its initial configuration. Three different regimes depending on the relative magnitude of gravitational and elastic forces are identified.
[Phys. Rev. Fluids 3, 104102] Published Tue Oct 30, 2018
Slip-flow lattice-Boltzmann simulations in ducts and porous media: A full rehabilitation of spurious velocities
Author(s): M. Aminpour, S. A. Galindo-Torres, A. Scheuermann, and L. Li
Slip flow in ducts and porous media is simulated using lattice-Boltzmann method incorporated with interfacial force models. The dependence of the results on the viscosity, LBM scheme (D3Q15 and D3Q19) and the relaxation time model (single- or multirelaxation time) is investigated. The severity of sp...
[Phys. Rev. E 98, 043110] Published Mon Oct 29, 2018
Author(s): Zakaria Boujja, Chaouqi Misbah, Hamid Ez-Zahraouy, Abdelilah Benyoussef, Thomas John, Christian Wagner, and Martin Michael Müller
We present a numerical study of the time-dependent motion of a two-dimensional vesicle in a channel under an imposed flow. In a Poiseuille flow the shape of the vesicle depends on the flow strength, the mechanical properties of the membrane, and the width of the channel as reported in the past. This...
[Phys. Rev. E 98, 043111] Published Mon Oct 29, 2018
Author(s): Wenli Di, Zehui Zhang, Lin Li, Kejun Lin, Jun Li, Xiaoguang Li, Bernard P. Binks, Xiaopeng Chen, and Duyang Zang
Experiments shows that with increasing sound intensity, an acoustically levitated drop buckles into a bowl shape and experiences a drastic expansion and closure, leading to the formation of an air bubble. This is attributed to the enhanced suction effect at the film rim due to the occurrence of resonance with sound field.
[Phys. Rev. Fluids 3, 103606] Published Mon Oct 29, 2018