# Latest papers in fluid mechanics

### Colloidal particle electrorotation in a nonuniform electric field

Author(s): Yi Hu, Petia M. Vlahovska, and Michael J. Miksis

A model to study the dynamics of colloidal particles in nonuniform electric fields is proposed. For an isolated sphere, the conditions and threshold for sustained (Quincke) rotation in a linear direct current (dc) field are determined. Particle dynamics becomes more complex with increasing electric ...

[Phys. Rev. E 97, 013111] Published Mon Jan 22, 2018

### Transitional region of a round synthetic jet

Author(s): Xi Xia and Kamran Mohseni

Experimental observations suggest the existence of an extended transitional region, as far as 30–50 diameter from a synthetic jet exit, where the spreading and decay rates are significantly enhanced over a continuous jet.

[Phys. Rev. Fluids 3, 011901(R)] Published Mon Jan 22, 2018

### Rheology of suspensions of viscoelastic spheres: Deformability as an effective volume fraction

Author(s): Marco E. Rosti, Luca Brandt, and Dhrubaditya Mitra

Simulations show that a suspension of deformable incompressible spheres in a Newtonian fluid displays shear-thinning and that this can be understood in terms of a reduction of the effective volume fraction occupied by the suspended spheres due to their deformation.

[Phys. Rev. Fluids 3, 012301(R)] Published Mon Jan 22, 2018

### Secondary flow vortical structures in a ${180}^{∘}$ elastic curved vessel with torsion under steady and pulsatile inflow conditions

Author(s): Mohammad Reza Najjari and Michael W. Plesniak

Multiple vortex-pair morphologies were studied using particle image velocimetry in steady and pulsatile flows through elastic curved vessels. Torsion effects were more profound than local vessel compliance (elasticity) effects. Torsion induces asymmetry in the vortical structures and causes like-signed vortices to merge.

[Phys. Rev. Fluids 3, 013101] Published Mon Jan 22, 2018

### Aeroelastic deformation of a perforated strip

Author(s): M. Guttag, H. H. Karimi, C. Falcón, and P. M. Reis

The aerodynamic drag and consequent deformation of a perforated flexible strip are studied with a combination of wind-tunnel experiments and numerical simulations. Increasing the porosity of the strips causes a reduction in the local drag coefficient similar to that seen in rigid perforated plates.

[Phys. Rev. Fluids 3, 014003] Published Mon Jan 22, 2018

### Hamiltonian bifurcation perspective on two interacting vortex pairs: From symmetric to asymmetric leapfrogging, period doubling, and chaos

Author(s): Brandon Whitchurch, Panayotis G. Kevrekidis, and Vassilis Koukouloyannis

Leapfrogging occurs, for example, in smoke or bubble rings. We model it in two dimensions with two interacting vortex pairs. Varying the vortices initial positions, we observe instabilities and bifurcations of leapfrogging along with other features including walkabout, braiding and chaotic motions.

[Phys. Rev. Fluids 3, 014401] Published Mon Jan 22, 2018

### Turbulence intensities in large-eddy simulation of wall-bounded flows

Author(s): H. J. Bae, A. Lozano-Durán, S. T. Bose, and P. Moin

We study the effect of wall boundary conditions on turbulence intensities in the context of wall-modeled large-eddy simulations. It is shown that the use of a slip boundary condition at the wall alleviates the well known turbulence intensity over-/under-prediction in coarse large-eddy simulations.

[Phys. Rev. Fluids 3, 014610] Published Mon Jan 22, 2018

### Publisher's Note: Poiseuille flow over a wavy surface [Phys. Rev. Fluids <b>2</b>, 124102 (2017)]

Author(s): Simon J. Haward, Amy Q. Shen, Jacob Page, and Tamer A. Zaki

[Phys. Rev. Fluids 3, 019901] Published Mon Jan 22, 2018

### Evolution of nonconformal Landau-Levich-Bretherton films of partially wetting liquids

Author(s): Michiel T. Kreutzer, Maulik S. Shah, Pravien Parthiban, and Saif A. Khan

Partially wetting thin films that are connected to plateau borders are described. The lifetimes of such films are found by matching the regimes of early capillary thinning and later collapse due to intermolecular forces.

[Phys. Rev. Fluids 3, 014203] Published Fri Jan 19, 2018

### Structure of high and low shear-stress events in a turbulent boundary layer

Author(s): G. Gomit, R. de Kat, and B. Ganapathisubramani

The structure of high and low shear-stress events in a turbulent boundary layer is investigated by means of simultaneous wide-field particle image velocimetry and wall-shear stress measurements. Contributions of the small and large scales are discussed based on a scale decomposition of the velocity field.

[Phys. Rev. Fluids 3, 014609] Published Fri Jan 19, 2018

### Impact of state-specific flowfield modeling on atomic nitrogen radiation

Author(s): Christopher O. Johnston and Marco Panesi

Removing typically-applied approximations (quasi-steady-state electronic levels and local escape factors) noticeably impacts the predicted shock-layer radiative heating to the afterbody region of Earth entry vehicles.

[Phys. Rev. Fluids 3, 013402] Published Thu Jan 18, 2018

### Cascades of energy and helicity in axisymmetric turbulence

Author(s): Bo Qu, Aurore Naso, and Wouter J. T. Bos

Axisymmetric turbulence shares features with both two- and three-dimensional flows. A spectral analysis shows the presence of a dual energy-helicity cascade, with energy transferred to the large scales and helicity to the small ones.

[Phys. Rev. Fluids 3, 014607] Published Thu Jan 18, 2018

### Secondary flows in turbulent boundary layers over longitudinal surface roughness

Author(s): Hyeon Gyu Hwang and Jae Hwa Lee

Inspection of spatial features of secondary flows in a turbulent boundary layer over longitudinal surface roughness shows that secondary flow size is mostly determined by the valley width and the rotational sense of secondary flows is affected by the turbulent transport term in the energy budget.

[Phys. Rev. Fluids 3, 014608] Published Thu Jan 18, 2018

### Model for the growth and the oscillation of a cavitation bubble in a spherical liquid-filled cavity enclosed in an elastic medium

Author(s): Alexander A. Doinikov, Benjamin Dollet, and Philippe Marmottant

Equations are derived that describe the growth and subsequent damped oscillation of a cavitation bubble in a liquid-filled cavity surrounded by an elastic solid. It is assumed that the nucleation and the growth of the bubble are caused by an initial negative pressure in the cavity. The liquid is tre...

[Phys. Rev. E 97, 013108] Published Wed Jan 17, 2018

### Persistence of local anisotropy of passive scalars in wall-bounded flows

Author(s): Emmanuel Germaine, Laurent Mydlarski, and Luca Cortelezzi

A persistent small-scale anisotropy of turbulent passive scalar fields, which is independent of the scalar field initial conditions, is observed in direct numerical simulations of fully developed channel flow, even after the flow has undergone substantial mixing, and is attributed to the mean velocity gradient.

[Phys. Rev. Fluids 3, 014606] Published Wed Jan 17, 2018

### Generalized derivation of the added-mass and circulatory forces for viscous flows

Author(s): Eric Limacher, Chris Morton, and David Wood

The added-mass concept can be validly applied to viscous flows, provided that the circulatory-force expression accounts for image vorticity. The relationship between added mass and image vorticity is explored, and the most appropriate physical interpretation of added mass is discussed.

[Phys. Rev. Fluids 3, 014701] Published Wed Jan 17, 2018

### Kullback-Leibler divergence measure of intermittency: Application to turbulence

Author(s): Carlos Granero-Belinchón, Stéphane G. Roux, and Nicolas B. Garnier

For generic systems exhibiting power law behaviors, and hence multiscale dependencies, we propose a simple tool to analyze multifractality and intermittency, after noticing that these concepts are directly related to the deformation of a probability density function from Gaussian at large scales to ...

[Phys. Rev. E 97, 013107] Published Tue Jan 16, 2018

### Derivation of Zagarola-Smits scaling in zero-pressure-gradient turbulent boundary layers

Author(s): Tie Wei and Yvan Maciel

The Zagarola-Smits scaling is derived directly from a detailed analysis of the mass and mean momentum balance in the outer region of the zero-pressure-gradient turbulent boundary layer.

[Phys. Rev. Fluids 3, 012601(R)] Published Tue Jan 16, 2018

### Einstein viscosity with fluid elasticity

Author(s): Jonas Einarsson, Mengfei Yang, and Eric S. G. Shaqfeh

Adding a small amount of rigid particles to a viscoelastic fluid leads to interesting suspension rheology, because the gradients near the particles induce elastic stresses in the fluid phase. We derive the viscosity of a dilute suspension of spheres by perturbation theory for a weakly elastic fluid.

[Phys. Rev. Fluids 3, 013301] Published Tue Jan 16, 2018

### Transition between quasi-two-dimensional and three-dimensional Rayleigh-Bénard convection in a horizontal magnetic field

Author(s): Tobias Vogt, Wataru Ishimi, Takatoshi Yanagisawa, Yuji Tasaka, Ataru Sakuraba, and Sven Eckert

Rayleigh-Bénard convection is studied in a liquid metal exposed to a horizontal magnetic field. Declining field strength at a given Ra number enables the development of diverse flow oscillations, which are attributed to two-dimensional variations of the roll structure and emerging 3D flow effects.

[Phys. Rev. Fluids 3, 013503] Published Tue Jan 16, 2018