Latest papers in fluid mechanics
Three-dimensional transition of zero-pressure-gradient boundary layer by impulsively and nonimpulsively started harmonic wall excitation
Author(s): Pushpender Sharma, Tapan K. Sengupta, and Swagata Bhaumik
A three-dimensional (3D) transition route for zero-pressure-gradient boundary layer over a flat plate is computationally investigated, for impulsive and nonimpulsive startup of harmonic wall excitation. A monochromatic frequency of excitation is chosen to perturb the boundary layer. The exciter plac...
[Phys. Rev. E 98, 053106] Published Mon Nov 26, 2018
Author(s): Han Luo, Israel B. Sebastião, Alina A. Alexeenko, and Sergey O. Macheret
This paper presents a new implementation of the Macheret-Fridman dissociation model for the direct simulation Monte Carlo method to model thermal nonequilibrium dissociation reactions. We find good agreement with recent quasi-classical trajectory calculations and recent experimental results.
[Phys. Rev. Fluids 3, 113401] Published Mon Nov 26, 2018
Author(s): Jacek K. Wrobel, Michael R. Booty, Michael Siegel, and Qiming Wang
A surfactant coated drop is drawn through an aperture by a converging flow. Under suitable conditions that have also been investigated in a series of independently led experiments, the drop tip emits a thin tipstreaming thread that later breaks up into near-monodisperse droplets.
[Phys. Rev. Fluids 3, 114003] Published Mon Nov 26, 2018
Author(s): Xu Guo, Juchun Ding, Xisheng Luo, and Zhigang Zhai
Evolution of a shocked inverse-chevron interface is studied experimentally, and the effect of vertex angle is highlighted. A new nonlinear model is constructed and provides a better prediction of interface growth than previous models.
[Phys. Rev. Fluids 3, 114004] Published Mon Nov 26, 2018
Steady two-dimensional free-surface flow over semi-infinite and finite-length corrugations in an open channel
Author(s): Jack S. Keeler, Benjamin J. Binder, and Mark G. Blyth
Steady free-surface flow over a semi-infinite and finite corrugated bottom is considered. It is demonstrated that by varying the Froude number a wide range of nontrivial solutions can be constructed, including generalized hydraulic falls, table-top solitons, and perturbed solitary waves.
[Phys. Rev. Fluids 3, 114804] Published Mon Nov 26, 2018
Author(s): Kathy Prestridge
Variable-density has important physical effects on turbulence, including driving mixing from small to large scales. Many compressible and variable-density flow applications cannot be simulated directly. Recent experimental measurements have implications for modeling and underresolved simulations.
[Phys. Rev. Fluids 3, 110501] Published Wed Nov 21, 2018
Author(s): Rui Luo, Yun Chen, and Sungyon Lee
When a mixture of noncolloidal particles and oil displaces air inside a Hele-Shaw cell, particles accumulate on the interface and cause fingering by generating an unstable viscosity gradient inside the suspension. A review and new data of the fingering onset and evolution are presented.
[Phys. Rev. Fluids 3, 110502] Published Wed Nov 21, 2018
Author(s): J. Eggers
The image of a turbulent jet reveals complex spatial patterns, which result from the decay of turbulent eddies into smaller and smaller structures. Here we lay out a road map to describe such patterns as a result of singularities which possess both a nontrivial spatial structure, and exhibit instability as they progress toward smaller and smaller scales.
[Phys. Rev. Fluids 3, 110503] Published Wed Nov 21, 2018
Author(s): Detlef Lohse
This paper sketches my personal scientific bubble journey, starting with single-bubble sonoluminescence, continuing with sound emission and scattering of bubbles, cavitation, snapping shrimp, impact events, air entrainment, and surface micro- and nanobubbles, and finally arriving at effective force models for bubbles and dispersed bubbly two-phase flow.
[Phys. Rev. Fluids 3, 110504] Published Wed Nov 21, 2018
Author(s): Anne-Laure Biance and Oriane Bonhomme
Liquid transport in a dry foam, a deformable porous material, in the presence of an applied electric field, is computed in the limits of rigid and mobile interfaces. The evolution of the liquid distribution is diffusive-like and significantly affected by the hydrodynamic boundary conditions.
[Phys. Rev. Fluids 3, 110505] Published Wed Nov 21, 2018
Author(s): David R. Dowling
Since the development of propagating-wave-based remote sensing more than a century ago, signal analysis has been limited to in-band recorded frequencies. However, this limitation is artificial. A new discovery from the realm of sonar shows that remote sensing is possible at out-of-band frequencies.
[Phys. Rev. Fluids 3, 110506] Published Wed Nov 21, 2018
Author(s): Andrea Gruber, Edward S. Richardson, Konduri Aditya, and Jacqueline H. Chen
Flashback is a key operational and safety issue for modern low-emission burners. With direct numerical simulations we study upstream flame movement through the turbulent flow within a channel and address the marked change in flashback behavior when the fuel and oxidant mixture is not homogeneous.
[Phys. Rev. Fluids 3, 110507] Published Wed Nov 21, 2018
Author(s): Jeffrey F. Morris
A scenario in which shear thickening results from a transition of interactions between suspended particles from lubricated to frictional (LF) with increasing stress is described, with a presentation of primary results and a perspective on outstanding questions which are raised by the LF mechanism.
[Phys. Rev. Fluids 3, 110508] Published Wed Nov 21, 2018
Author(s): Matthew P. Juniper
The power density in a rocket engine is 50 GW/m3. If flame oscillations lock into the acoustic modes of the chamber, the resultant noise can blow up the engine. This paper explains pedagogically, with example code, how best to use adjoint methods to passively control this thermoacoustic instability.
[Phys. Rev. Fluids 3, 110509] Published Wed Nov 21, 2018
Visualization study of thermal counterflow of superfluid helium in the proximity of the heat source by using solid deuterium hydride particles
Author(s): P. Švančara, P. Hrubcová, M. Rotter, and M. La Mantia
An experimental investigation of steady-state thermal counterflow of superfluid 4He indicates that, in the range of investigated parameters, interactions between flow-probing particles and tangles of quantized vortices are appreciably influenced not only by the tangle geometry but also by the particle inertia.
[Phys. Rev. Fluids 3, 114701] Published Wed Nov 21, 2018
Author(s): Giulio Ghirardo and Mirko R. Bothien
An investigation of fluctuations occurring in rotationally symmetric systems draws a link between these fluctuations and light polarization, two-state quantum systems, and quaternion numbers. An ansatz is proposed to study this class of problems and is applied it to azimuthal acoustic instabilities in an annular combustion chamber.
[Phys. Rev. Fluids 3, 113202] Published Tue Nov 20, 2018
Author(s): J. J. J. Gillissen and H. J. Wilson
A theoretical study shows that adding disk-shaped particles to the fluid between counter-rotating cylinders reduces the onset-speed for secondary flow.
[Phys. Rev. Fluids 3, 113903] Published Tue Nov 20, 2018
Author(s): Byunghang Ha (하병항), Daniel P. DePonte, and Juan G. Santiago
A design for and experimental study of microfluidic nozzles that generate thin liquid sheet jets is presented. A parametric study is conducted by varying nozzle geometry, flow rate, and fluid type, and scaling theories to scale and predict jet sheet thickness, width, and length are proposed.
[Phys. Rev. Fluids 3, 114202] Published Tue Nov 20, 2018
Author(s): Anupam Gupta, Pascale Magaud, Christine Lafforgue, and Micheline Abbas
If flow inertia is finite at the particle scale in a channel, particles align parallel to the flow streamlines, forming stable trainlike structures near the walls at low concentration. A numerical investigation finds that hydrodynamic interactions prohibit train formation at lengths exceeding the channel height.
[Phys. Rev. Fluids 3, 114302] Published Tue Nov 20, 2018
Author(s): Markus Klein and Massimo Germano
An exact relation between the Reynolds stress and the resolved stress of filtered data is derived and tested in order to quantify the interference effect between mean and subfilter scales. Besides the well-known resolved and subfilter stresses, two additional terms appear in the decomposition.
[Phys. Rev. Fluids 3, 114606] Published Tue Nov 20, 2018