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Microorganisms navigate complex fluid environments, impacting medical and industrial applications. Here, the authors use Lattice Boltzmann simulations to reveal how flexible polymers dramatically enhance rotational motion and reduce propulsion in squirmers, examining the role of inertial and viscous forces impacting the motion of squirmers in complex environments.

Active fluids, such as bacterial suspensions, exhibit chaotic flows at low Reynolds number - a phenomenon known as active turbulence. Here, the authors show a discontinuous transition from laminar to chaotic flows in unconfined active nematics.

High-pressure measurements of the electrical conductivity of (Mg,Fe)O, used as an analogue for basal magma ocean material, indicate that the conductivity is high enough to produce a dynamo much stronger than a core-driven dynamo for super-Earths larger than 3–6 Earth masses.

Morkovin’s hypothesis establishes a comparison between incompressible and compressible flows and is essential for understanding supersonic and hypersonic turbulence. In this work, the authors present the measurements of wall-normal fluctuations that support the hypothesis proposed in 1962.

Vortex dynamics and mutual friction in quantum fluids are intimately connected to the fundamental properties of superfluids. Here, the authors reveal previously unexplored mechanisms underlying the mutual friction coefficients in ultracold Fermi superfluids in the unitary limit, suggesting bound quasiparticles within the vortex core play a significant role.

Droplet impacts shape technologies from erosion to bioprinting. Here, authors show a scaling crossover in peak impact force on soft substrates, from inertial to Hertzian, unified by a similarity parameter. The proposed stress tomography provides a practical map to design impact-resistant processes.

3D-printed gel microcilia arrays printed by two-photon polymerization and composed of a soft acrylic acid-co-acrylamide hydrogel with a nanometre-scale network structure are shown to respond to low-voltage electrical stimuli within milliseconds, enabling dynamic individual control and non-reciprocal 3D motion.

Most active particles studied to date lack the ability to undergo controlled shape transformations and control over their propulsion in response to environmental stimuli. Here, the authors present a class of active particles made from stimuli-responsive materials that exhibit fully reversible shape-dependent propulsion.

It is commonly believed that the flow of water or air with large Reynolds number can only have one turbulent state because of large fluctuations. Here, Huisman et al. disprove this theory in experiments by identifying the existence of multiple stable states in highly turbulent Taylor–Couette flow.

Whether rivers are speeding up or slowing down in a warming Arctic is unclear, but has implications for carbon cycling and infrastructure. This study finds divergent behaviour in migration rates for rivers in discontinuous versus continuous permafrost, driven by changes in permafrost thaw and river ice.

Identifying jets originating from heavy quarks plays a fundamental role in hadronic collider experiments. In this work, the ATLAS Collaboration describes and tests a transformer-based neural network architecture for jet flavour tagging based on low-level input and physics-inspired constraints.

Small-scale vorticity dynamics are central to turbulence, but their transient and chaotic nature makes direct measurement and control extremely challenging. By using magnetically driven particles, authors uncover stochastic resonance and a symmetry-breaking mechanism that may enable both control of particle dynamics and a magnetic resonance- based method for probing turbulence at its smallest scales.

Simulations of turbulent flows are relevant for aerodynamic and weather modeling, however challenging to capture flow dynamics in the near wall region. To solve this problem, the authors propose a multi-agent reinforcement learning approach to discover wall models for large-eddy simulations.

Turbulence effects explored use macroscale systems in general. Here the authors generate a turbulent plasma using laser irradiation of a solid target and study the dynamics of the plasma flow at the micron-scale by using scattering of an XFEL beam.

Cavitation is the formation of vapour bubbles within a liquid and is undesirable in many industrial applications. Here Stiegeret al. show how the anisotropic fluids influence this process in a nematic liquid crystal and find that orientational ordering of molecules can tune the onset of cavitation.

The control of turbulent flows is crucial for improving efficiency in engineering systems. Here, authors show in a numerical simulation that using deep reinforcement learning to control surface actuators can successfully mitigate turbulent flow separation, paving the way for new advancements in turbulence control.

Here the authors report a that sprint interval exercise triggers mitochondrial stress and quality control in skeletal muscle in young healthy men, promoting enhanced mitochondrial function and a remodelling after 8 weeks of training.

Early-Earth geometry models are presented, producing magnetic field intensity and morphologies agreeing with palaeomagnetic data in the deep past and demonstrating the negligible role of fluid viscosity in the Earth’s early geodynamo.

Coordinated X-ray and radio observations reveal that disk winds and jets occur mutually exclusively in 4U 1630–472, providing new observational constraints on the interplay between different modes of outflow in X-ray binaries.

Experiments, asymptotic theory and computer simulations of wall-bounded shear flow uncover a bifurcation scenario that explains the transition from localized turbulent patches to fully turbulent flow.

Bacterial biofilms can form as streamers - filamentous structures suspended in fluids that withstand intense hydrodynamic stresses - enabling colonisation of flow-exposed environments such as medical devices and filters. The authors demonstrate that streamers exhibit stress hardening driven by extracellular DNA and modulated by RNA, providing a physical mechanism for both short- and long-term mechanical adaptation.

Whether a turbulent flow would inevitably develop singular behavior at the smallest length scales is an ongoing intriguing debate. Using large-scale numerical simulations, Buaria et al. find an unexpected non-linear mechanism which counteracts local vorticity growth instead of enabling it.

Turbulence modelling is an essential flow simulation tool, but is typically dependent on physical insight and engineering intuition. Novati et al. develop a multi-agent reinforcement learning approach for learning turbulence models that can generalize across grid sizes and flow conditions.

A lung-on-a-chip device containing immune cells and stromal cells mimics the small airways, recapitulating human immune response to severe H1N1 infection.

Particles in turbulence, as encountered in the atmosphere or the oceans, experience strongly varying local flow conditions over time. Bentkamp et al. show that this statistical complexity can be broken down into simpler parts, allowing for insights into the space-time structure of turbulent flows.

A challenge of magnetically-actuated devices is to obtain different behaviours from each component under the same driving field. Here the authors tune the dipolar interactions between rotors to obtain different rotational behaviours when actuated by a magnetic field leading to complex collective dynamics.

The importance of optimizing the contact between catalyst particles, hydrogen and plastic melt in polyolefin chemical recycling has been overlooked, leading to suboptimal performance. The authors develop a criterion based on the dimensionless power number to optimize catalyst effectiveness. Stirring conditions can now be selected to treat commercial-grade polyethylene and polypropylene.