Physical Review Fluids

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Recent articles in Physical Review Fluids
Updated: 23 hours 43 min ago

Experimental and numerical determination of Darcy's law for yield stress fluids in porous media

Wed, 06/05/2019 - 11:00

Author(s): D. Bauer, L. Talon, Y. Peysson, H. B. Ly, G. Batôt, T. Chevalier, and M. Fleury

Experiments and three-dimensional numerical simulations of yield stress fluids in heterogeneous porous media show that, as a result of this disorder, the fluid flows through a single channel near a critical pressure. Beyond that, the number of open channels increases with the pressure applied.

[Phys. Rev. Fluids 4, 063301] Published Wed Jun 05, 2019

Slightly deformable Darcy drop in linear flows

Wed, 06/05/2019 - 11:00

Author(s): Y.-N. Young, Yoichiro Mori, and Michael J. Miksis

When a poroelastic spherical drop is under a uniaxial extension flow or a shear flow, the elastic network deforms in response to the external fluid viscous stress. A small-deformation analysis is conducted to investigate effects of interfacial slip and permeability on flow around the drop.

[Phys. Rev. Fluids 4, 063601] Published Wed Jun 05, 2019

Synthetic turbulent inflow generator using machine learning

Tue, 06/04/2019 - 11:00

Author(s): Kai Fukami, Yusuke Nabae, Ken Kawai, and Koji Fukagata

Machine-learning-based turbulence generators are developed to generate unsteady inflow conditions for turbulent flow simulations. The proposed method can provide inflow conditions with reasonable turbulence statistics without spurious periodicity and at a low computational cost.

[Phys. Rev. Fluids 4, 064603] Published Tue Jun 04, 2019

Faraday waves on band pattern under zero gravity conditions

Mon, 06/03/2019 - 11:00

Author(s): T. Lyubimova, A. Ivantsov, Y. Garrabos, C. Lecoutre, and D. Beysens

Coupled Faraday waves can develop under weightlessness on liquid-vapor bands induced by vibrations. The instability appears above a threshold that is determined by theoretical analysis and numerical simulation. It compares well with sounding rocket experiments in CO2 near its critical point.

[Phys. Rev. Fluids 4, 064001] Published Mon Jun 03, 2019

Transport across a bathymetric interface in quasi-two-dimensional flow

Mon, 06/03/2019 - 11:00

Author(s): Lei Fang and Nicholas T. Ouellette

In many geophysical situations, variable bathymetry can affect surface transport and mixing. Experiments show that the effect of bathymetry is to produce a porous transport barrier leading to asymmetric transport. These results may help to explain the dynamics of phenomena such as ocean dead zones.

[Phys. Rev. Fluids 4, 064501] Published Mon Jun 03, 2019

Statistical properties of an incompressible passive vector convected by isotropic turbulence

Mon, 06/03/2019 - 11:00

Author(s): Jingyuan Yang, Toshiyuki Gotoh, Hideaki Miura, and Takeshi Watanabe

Statistical properties of an incompressible passive vector in isotropic turbulence are compared with the velocity and passive scalar in order to explore the physics behind their differences and similarities.

[Phys. Rev. Fluids 4, 064601] Published Mon Jun 03, 2019

Emergence of skewed non-Gaussian distributions of velocity increments in isotropic turbulence

Mon, 06/03/2019 - 11:00

Author(s): W. Sosa-Correa, R. M. Pereira, A. M. S. Macêdo, E. P. Raposo, D. S. P. Salazar, and G. L. Vasconcelos

A theoretical framework, the H-theory, is applied to describe the skewed non-Gaussian distribution of velocity increments as a weighted mixture of asymmetric Gaussians. The weighing distribution is obtained from a hierarchical stochastic model of intermittency. Good agreement with direct numerical simulation data is found.

[Phys. Rev. Fluids 4, 064602] Published Mon Jun 03, 2019

Stability of inclined flow of a liquid film with soluble surfactants and variable mass density

Fri, 05/31/2019 - 11:00

Author(s): J. P. Pascal, S. J. D. D'Alessio, and E. Ellaban

Adding surfactant to clean fluid stabilizes the inclined flow. A theoretical study shows that beyond a critical level the flow is destabilized as more surfactant is added due to desorption from the surface. If the mass density of the fluid increases with surfactant concentration in the bulk, a later stabilizing stage occurs.

[Phys. Rev. Fluids 4, 054004] Published Fri May 31, 2019

Dynamics of particle migration in confined viscoelastic Poiseuille flows

Thu, 05/30/2019 - 11:00

Author(s): Antoine Naillon, Clément de Loubens, William Chèvremont, Samuel Rouze, Marc Leonetti, and Hugues Bodiguel

Quantitative experimental measurements are used to test the ability of theoretical development to predict the transverse velocity migration of particles in a confined Poiseuille flow, according to the viscoelastic constitutive parameters of dilute polymer solutions.

[Phys. Rev. Fluids 4, 053301] Published Thu May 30, 2019

Investigation of the structures in the unstable rotating-cone boundary layer

Thu, 05/30/2019 - 11:00

Author(s): K. Kato, T. Kawata, P. H. Alfredsson, and R. J. Lingwood

Experiments show that crossflow vortices in the boundary layer on a rotating wide cone start to meander before breakdown. The structural development of the overturning process of these vortices, where high-momentum upwelling of the vortices leads to transition to turbulence, is described in detail.

[Phys. Rev. Fluids 4, 053903] Published Thu May 30, 2019

Coexistence of multiple long-time solutions for two-dimensional laminar flow past a linearly sprung circular cylinder with a rotational nonlinear energy sink

Thu, 05/30/2019 - 11:00

Author(s): Antoine B. Blanchard, Lawrence A. Bergman, Alexander F. Vakakis, and Arne J. Pearlstein

Phase diagram showing the variation of the number of long-time solutions with Re and a dimensionless measure of spring stiffness. Each combination of symbol shape and color indicates a different set of such solutions, with the pentagons corresponding to three unsteady solutions and one steady one.

[Phys. Rev. Fluids 4, 054401] Published Thu May 30, 2019

Refinement of the logarithmic law of the wall

Thu, 05/30/2019 - 11:00

Author(s): F. Laadhari

A refinement of the logarithmic law for the mean velocity in canonical wall-bounded turbulent flows is presented. The relevant length scale in the overlap region is found to be based on the weighted mean velocity gradient instead of the classical length scale based on the wall friction velocity.

[Phys. Rev. Fluids 4, 054605] Published Thu May 30, 2019

Scaling of Reynolds stresses in a differentially heated vertical channel

Tue, 05/28/2019 - 11:00

Author(s): Tie Wei

Reexamination of some direct numerical simulation data for a turbulent differentially heated vertical channel finds that the components of the Reynolds stress scale with the product of the friction velocity and the maximum mean flow.

[Phys. Rev. Fluids 4, 051501(R)] Published Tue May 28, 2019

Strong vorticity fluctuations and antiferromagnetic correlations in axisymmetric fluid equilibria

Tue, 05/28/2019 - 11:00

Author(s): Peter B. Weichman

Equilibrium properties of axisymmetric flow in cylindrical (Taylor-Couette) geometries are studied using the methods of statistical mechanics. The system is constrained by an infinite number of conservation laws, leading to an intricate interplay between the toroidal (σ) and poloidal (ξ) flow fields.

[Phys. Rev. Fluids 4, 054703] Published Tue May 28, 2019

Active control of vortex shedding from a blunt trailing edge using oscillating piezoelectric flaps

Tue, 05/28/2019 - 11:00

Author(s): Bradley Gibeau, Charles Robert Koch, and Sina Ghaemi

Active control of vortex shedding from a blunt trailing edge is achieved experimentally using piezoelectric actuators. The system can suppress and amplify the vortex shedding pattern in the wake, as well as force near-wake symmetry. An application of closed-loop control is also demonstrated.

[Phys. Rev. Fluids 4, 054704] Published Tue May 28, 2019

Three-dimensional visualization of viscous fingering for non-Newtonian fluids with chemical reactions that change viscosity

Fri, 05/24/2019 - 11:00

Author(s): Sotheavuth Sin, Tetsuya Suekane, Yuichiro Nagatsu, and Anindityo Patmonoaji

Three-dimensional viscous fingering for miscible non-Newtonian fluids with and without chemical reactions were studied with a microfocus X-ray computed tomography scanner. We find that the area fraction of injected fluid in the reactive cases was lower than that in the nonreactive cases.

[Phys. Rev. Fluids 4, 054502] Published Fri May 24, 2019

Stability of arrays of bottom-heavy spherical squirmers

Wed, 05/22/2019 - 11:00

Author(s): D. R. Brumley and T. J. Pedley

A dense planar array of spherical microswimmers is studied analytically and numerically using pairwise lubrication interactions. Suspension dynamics are mediated through gravitational torques exerted on the cells and cell-cell repulsive forces, and they reveal stable, oscillatory, and chaotic states.

[Phys. Rev. Fluids 4, 053102] Published Wed May 22, 2019

Vortex-dynamical interpretation of anti-phase and in-phase flickering of dual buoyant diffusion flames

Wed, 05/22/2019 - 11:00

Author(s): Tao Yang, Xi Xia, and Peng Zhang

A study finds that for two adjacent buoyant flames the flickering mode transition from in-phase to anti-phase is caused by a transition of the inner-side vortex pattern from symmetric to staggered. This mechanism is similar to the instability in the wake of a bluff body that initiates the Karman vortex street.

[Phys. Rev. Fluids 4, 053202] Published Wed May 22, 2019

Invariant manifolds in stratified turbulence

Mon, 05/20/2019 - 11:00

Author(s): N. E. Sujovolsky, G. B. Mindlin, and P. D. Mininni

A low dimensional model for stratified turbulence predicts the existence of invariant manifolds for the evolution of temperature and velocity gradients. Fluid elements evolve preferentially along these manifolds, associated with stable regions and with regions prone to develop local convection.

[Phys. Rev. Fluids 4, 052402(R)] Published Mon May 20, 2019

Stabilization of unsteady flows by reduced-order control with optimally time-dependent modes

Mon, 05/20/2019 - 11:00

Author(s): Antoine Blanchard and Themistoklis P. Sapsis

The Optimally Time-Dependent (OTD) modes, a set of deformable orthonormal modes that track transient instabilities, are incorporated into a robust, inexpensive control algorithm that can steer any trajectory of a high-dimensional nonlinear system toward a fixed point of the governing equations.

[Phys. Rev. Fluids 4, 053902] Published Mon May 20, 2019