Physical Review Fluids
Role of hydrodynamic shear layer stability in driving combustion instability in a premixed propane-air backward-facing step combustor
Author(s): Santosh Hemchandra, Santosh Shanbhogue, Seunghyuck Hong, and Ahmed F. Ghoniem
With numerical methods and analysis of existing experimental results we show that combustion instability in a backward-facing step combustor can be maintained either with weak coupling between acoustic and hydrodynamic modes (semi-open loop) or with strong coupling (fully closed loop).
[Phys. Rev. Fluids 3, 063201] Published Mon Jun 18, 2018
Effects of finite spatial and temporal resolution in direct numerical simulations of incompressible isotropic turbulence
Author(s): P. K. Yeung, K. R. Sreenivasan, and S. B. Pope
A study combining spectral filtering and numerical simulations at enhanced spatial and/or temporal resolution is used to clarify the proper scaling of dissipation and enstrophy in forced incompressible isotropic turbulence.
[Phys. Rev. Fluids 3, 064603] Published Mon Jun 18, 2018
Author(s): Benjamin Cross, Chloé Barraud, Cyril Picard, Liliane Léger, Frédéric Restagno, and Élisabeth Charlaix
Experiments with a complex fluid in an oscillating atomic force microscope find that the wall slip is well characterised by a real Navier interfacial friction coefficient instead of the usual slip height.
[Phys. Rev. Fluids 3, 062001(R)] Published Fri Jun 15, 2018
From hindered to promoted settling in dispersions of attractive colloids: Simulation, modeling, and application to macromolecular characterization
Author(s): Andrew M. Fiore, Gang Wang, and James W. Swan
Immersed boundary simulations are used to study settling in dispersions of sticky colloids and to develop an empirical model for the settling rate that is in good agreement with experiments. The model is applied to characterize attractive interactions in concentrated macromolecular solutions.
[Phys. Rev. Fluids 3, 063302] Published Fri Jun 15, 2018
Author(s): P. M. Comiskey, A. L. Yarin, and D. Attinger
A theoretical model predicts forward blood spatter from a 9-mm bullet and favorably agrees with experimental data. Blood drop generation is explained through chaotic liquid disintegration built in the framework of percolation theory.
[Phys. Rev. Fluids 3, 063901] Published Fri Jun 15, 2018
Author(s): R. I. Mullyadzhanov, R. D. Sandberg, S. S. Abdurakipov, W. K. George, and K. Hanjalić
In direct numerical simulations of a turbulent jet, propagating helical waves which contain much of the energy are tracked from the near to the far field in order to find their scaling properties and dispersion laws.
[Phys. Rev. Fluids 3, 062601(R)] Published Thu Jun 14, 2018
[Phys. Rev. Fluids 3, 060001] Published Wed Jun 13, 2018
Author(s): Alexis Bougouin and Laurent Lacaze
The collapse of a granular column in a fluid shows that both the dynamics and the deposit shape depend on the aspect ratio, Stokes number, and grain-fluid density ratio. Classification of flow regimes and characterization of the associated dynamics are proposed through an experimental investigation.
[Phys. Rev. Fluids 3, 064305] Published Wed Jun 13, 2018
Author(s): Murali-Girija Mithun, Phoevos Koukouvinis, and Manolis Gavaises
A fully compressible three-phase cavitation model is developed to study the interaction between the cavitation and primary atomization. The simulations reveal that the developing cavitation condition with cyclic air entrainment is the most favourable condition for primary atomization.
[Phys. Rev. Fluids 3, 064304] Published Tue Jun 12, 2018
Author(s): Jeffrey Tithof, Benjamin C. Martell, and Douglas H. Kelley
Two-dimensional flow is often approximated by driving thin fluid layers electromagnetically. By comparing three common experimental configurations, it is shown that the single-layer and immiscible configurations minimize out-of-plane flow over a wider range of Reynolds numbers than miscible configurations.
[Phys. Rev. Fluids 3, 064602] Published Tue Jun 12, 2018
Author(s): Anita A. Dey, Yahya Modarres-Sadeghi, and Jonathan P. Rothstein
Elastic flow instabilities in the wake of a flexible cylinder can drive the motion of the cylinder, resulting in 1D and 2D oscillations. The time variation of the flow field and the state of stress in the fluid are shown using particle image tracking and flow-induced birefringence images.
[Phys. Rev. Fluids 3, 063301] Published Mon Jun 11, 2018
Rheology of dense granular flows in two dimensions: Comparison of fully two-dimensional flows to unidirectional shear flow
Author(s): Ashish Bhateja and Devang V. Khakhar
Numerical simulations of dense granular flows in three different planar geometries find that the μ-I scaling for the local viscosity is found to be valid for each geometry, but the data for the three geometries do not collapse to a single curve.
[Phys. Rev. Fluids 3, 062301(R)] Published Fri Jun 08, 2018
Author(s): Alexander Morozov, Davide Marenduzzo, and Ronald G. Larson
In this paper, we report an inertial instability that occurs in electro-osmotically driven channel flows. We assume that the charge motion under the influence of an externally applied electric field is confined to a small vicinity of the channel walls that, effectively, drives a bulk flow through a ...
[Phys. Rev. Fluids 3, 063702] Published Fri Jun 08, 2018
Influence of a thin compressible insoluble liquid film on the eddy currents generated by interacting surface waves
Author(s): Vladimir M. Parfenyev and Sergey S. Vergeles
Crossed surface waves generate eddy currents near the fluid surface owing to hydrodynamic nonlinearity. We studied how these currents penetrate into the fluid bulk and showed that a thin compressible insoluble liquid film presented on the fluid surface increases their intensity.
[Phys. Rev. Fluids 3, 064702] Published Fri Jun 08, 2018
Author(s): A. M. P. Boelens, A. Latka, and J. J. de Pablo
At atmospheric pressure, a droplet impacting on a surface produces a splash. Reducing the ambient pressure suppresses this splash. The pressure effect is not well understood and this is the first study to present an in-depth comparison between various theoretical splashing models and simulations.
[Phys. Rev. Fluids 3, 063602] Published Thu Jun 07, 2018
Electrohydrodynamic ionic wind, force field, and ionic mobility in a positive dc wire-to-cylinders corona discharge in air
Author(s): Nicolas Monrolin, Olivier Praud, and Franck Plouraboué
Particle image velocimetry of ionic wind produced by a positive dc corona in air is used to evaluate lift force, and results are consistent with a general theoretical expression previously found for net momentum transfer. Momentum transfer efficiency is found to be sensitive to the electrode aerodynamic wake and the electric field orientation.
[Phys. Rev. Fluids 3, 063701] Published Thu Jun 07, 2018
Author(s): Xiuxiu Lyu, Shucheng Pan, Xiangyu Hu, and Nikolaus A. Adams
With the Euler-Lagrangian coupled method we simulate homogeneous nucleation cavitation induced by shock reflection in a microchannel. Nucleation is found to occur in three stages: energy deposition, generation, and growth. Initial generation time is not found to depend strongly on shock intensity.
[Phys. Rev. Fluids 3, 064303] Published Thu Jun 07, 2018
Author(s): Fabian Reuter and Robert Mettin
A high-speed method for time-resolved measurements of wall shear rates providing microscopic resolution is presented. The wall shear rates produced by a single, collapsing cavitation bubble are studied.
[Phys. Rev. Fluids 3, 063601] Published Wed Jun 06, 2018
Author(s): Jacob Keller, Praveen Kumar, and Krishnan Mahesh
Results of a high-fidelity large eddy simulation are used to compute the far-field sound that results from the unsteady loading of a propeller operating at design condition. High levels of unsteadiness at the blade tip account for the majority of far-field sound.
[Phys. Rev. Fluids 3, 064601] Published Wed Jun 06, 2018
Author(s): S. Pasche, F. Avellan, and F. Gallaire
The dynamics of the helical vortex breakdown has revealed a Ruelle-Takens-Newhouse route to chaos coming from the nonlinear interactions of pure hydrodynamic modes. Global stability analysis, Fourier series decomposition, and time series analysis have been used to shed light on the dynamical states.
[Phys. Rev. Fluids 3, 064701] Published Wed Jun 06, 2018