Latest papers in fluid mechanics

Author(s): Dongxiao Zhao and Hussein Aluie

[Phys. Rev. Fluids 10, 029901] Published Tue Feb 04, 2025

Author(s): Sajjad Mohammadnejad and Sina Kheirkhah

How fast do turbulent premixed flames burn? This experimental investigation utilizes both active and passive turbulence generators to produce a wide range of turbulent flow characteristics for studying the scalar dissipation rate (the image), which is related to the burning velocity of premixed flames. Then, the spectral characteristics of the background turbulence, scalar dissipation rate, and the related burning velocity are presented, discussed, and compared. This study discusses the important role of large-scale turbulence in enhancing the burning velocity of turbulent premixed methane-air and hydrogen-enriched methane-air flames.

[Phys. Rev. Fluids 10, 023201] Published Mon Feb 03, 2025

Author(s): Oz Oshri

The intricate dynamics between thin sheets and compressible fluids plays a pivotal role in microelectromechanical systems and microfluidic switches, where precise control of fluid dynamics and structural movement is essential. In this study we present an analytical model that integrates the elasticity of thin sheets with the hydrodynamics of compressible fluids to investigate how material properties and compression influence the system’s vibrational modes.

[Phys. Rev. Fluids 10, 013905] Published Fri Jan 31, 2025

Author(s): Albane Théry, Andres Zambrano, Eric Lauga, and Roberto Zenit

Microorganisms often navigate in heterogeneous complex fluids, such as mucus or soil. The heterogeneity affects swimming in surprising ways. In this work we use experiments and mathematical modeling to understand the effect of suspended particles on the efficiency of helical propulsion. Strikingly, we find that suspensions can significantly enhance propulsion.

[Phys. Rev. Fluids 10, 013101] Published Wed Jan 29, 2025

Author(s): Radha S, Swarup Barik, and Nanda Poddar

Chemical reactions significantly affect the solute dynamics in the couple stress fluid flow. Using multiscale homogenization, our findings highlight how combined bulk and wall chemical reactions significantly reduce the solute concentration for all values of the couple stress parameter in flows between parallel plates. Bulk and wall chemical reactions consume the solute across the channel, and at the boundaries, these reactions override the effects of couple stress, ensuring precise control over concentration profiles. Crucially, the couple stress effect remains impactful for all reaction conditions, opening new frontiers in advanced fluid system design.

[Phys. Rev. Fluids 10, 014502] Published Wed Jan 29, 2025

Author(s): Simon Hartmann and Uwe Thiele

The article presents a mesoscopic hydrodynamic model for a spreading drop of volatile partially wetting liquid on a solid porous substrate. The model describes the coupled dynamics of the the three-phase system in terms of the drop height profile, the vertically averaged saturation profile in the porous layer and the vertically averaged vapor density above the substrate. Our approach is based on the gradient dynamics framework widely used for modeling thin liquid films. After developing the model, we discuss a selection of theoretical and numerical results, e.g., the resulting sorption isotherm or a simulation of coupled spreading, imbibition, and evaporation dynamics.

[Phys. Rev. Fluids 10, 014003] Published Mon Jan 27, 2025

Author(s): Giulio Foggi Rota, Alessandro Chiarini, and Marco Edoardo Rosti

We simulate the dynamics of a flexible stem submerged under a surface gravity wave. Varying the rigidity of the stem, we explore its motion in the drag-dominated regime with realistic air and water properties. A stiffer stem maintains on average a straight configuration and exhibits streamwise oscillations in phase-opposition with the wave, moving symmetrically with respect to the vertical direction. Conversely, a more compliant stem reconfigures under the influence of the Stokes drift, bending forward and breaking the symmetry, and exhibits oscillations that are more coherent with the surrounding flow field. Resonance is observed at the transition between the two regimes.

[Phys. Rev. Fluids 10, 014301] Published Mon Jan 27, 2025

Author(s): Li-Hsuan Chang and Satish Kumar

We focus on how cavity shape, evaporation rate, and thermal Marangoni flow affect particle deposition when the contact line is free to move. A lubrication- theory-based model is developed to derive evolution equations for the droplet height and vertically averaged particle concentration. Our model shows that a pressure maximum appears at the droplet edge as the evaporation rate or thermal Marangoni flows increase, or as the cavity depth decreases. The resulting inward flow causes the contact line to depin, which leads to an increase in the uniformity of particle deposition but also to the occurrence of a pinch point (a sharp local minimum of particle number density) near the droplet edge.

[Phys. Rev. Fluids 10, 014002] Published Fri Jan 24, 2025

Author(s): Samvit Kumar, Simon Toedtli, Tamer A. Zaki, and Gregory L. Eyink

The detailed Josephson-Anderson relation, which equates instantaneously the volume-integrated vorticity flux and the work by pressure drop, has been the key to drag reduction in superconductors and superfluids. We employ a classical version of this relation to investigate the dynamics of polymer dra…

[Phys. Rev. E 111, 015105] Published Fri Jan 24, 2025

Author(s): Eric Lauga and Beverley McKeon

[Phys. Rev. Fluids 10, 010001] Published Thu Jan 23, 2025

Author(s): Osher Arbib and Naomi Oppenheimer

When particles suspended in a fluid are heated, their localized temperature modifies the fluid’s viscosity in nontrivial ways. Einstein famously showed that adding particles to a fluid increases its viscosity. This work demonstrates that heating these particles can cause the viscosity to increase, decrease, or remain unchanged, depending on the temperature gradient. Moreover, an uneven heat distribution on the particles gives rise to surprising effects — making the fluid’s behavior directionally dependent and inducing what is known as odd viscosity. These findings open new avenues for controlling fluid flow.

[Phys. Rev. Fluids 10, 013301] Published Thu Jan 23, 2025

Author(s): Henrik Kiefer, Domenico Vitali, Benjamin A. Dalton, Laura Scalfi, and Roland R. Netz

The relation between the frequency-dependent friction of a molecule in a liquid and the hydrodynamic properties of the liquid is fundamental for molecular dynamics. We investigate this connection for a water molecule moving in liquid water using all-atomistic molecular dynamics (MD) simulations and …

[Phys. Rev. E 111, 015104] Published Thu Jan 23, 2025

Author(s): S. S. Liu, Y. B. Sun, C. Wang, J. K. Shao, and J. J. Tao

In this Letter, we report on the induction of aluminum combustion within supercritical water, facilitated by an underwater explosion bubble. This bubble, initiated using an aluminum-wire electrical discharge in a water-filled tank, typically spans tens of centimeters and undergoes oscillatory dynami…

[Phys. Rev. E 111, L013101] Published Wed Jan 22, 2025

Author(s): J. Sánchez-Rodríguez and F. Gallaire

Archetypal falling behaviors of impervious objects are classified into four modes: fluttering, tumbling, steady descent, and chaotic motion. We present in this paper an experimental result of stability induced by porosity and permeability. We discover that by drilling different porosity patterns, we can avoid tumbling and chaotic behavior in plates that, due to their inertia and Reynolds values, should tumble while falling according to the regime diagram of impervious plates. Instead, the majority of the plates flutter and a few even descend steadily.

[Phys. Rev. Fluids 10, 013904] Published Tue Jan 21, 2025

Author(s): Abdelhalim Abdeldayem, Thijs Bon, Raúl Bayoán Cal, and Johan Meyers

The valley-mountain arrangement excites secondary vortices when interacting with the atmospheric boundary layer. In this paper we develop an analytical model to predict these secondary vortices in the case of thermal stratification. The model was compared to recent direct numerical simulations available in the literature which studied secondary motions in channel flow for a wide range of Reynolds and Richardson numbers. The model showed robust performance for the range of cases considered, showing error less than 5% for the temperature and below 20% for velocity in most cases.

[Phys. Rev. Fluids 10, 014605] Published Tue Jan 21, 2025