All articles tagged with #fluid dynamics
Physicists have rebuilt fluid dynamics from the ground up with an effective field theory based on fundamental symmetries, showing the Navier–Stokes equations are emergent rather than exact and connecting fluids to cosmology, black holes, and exotic states to predict new behaviors and refine heat diffusion.
Japanese researchers suspended thousands of colloidal particles in water between microfabricated electrodes and applied an alternating electric field, which caused mixed-size particles to form self-propelled pairs and chase one another, effectively breaking action–reaction symmetry for about an hour. When all particles were the same size, interactions remained reciprocal and the system crystallized; with mixed sizes, particles clustered and then split repeatedly. The finding could inform programmable materials and microrobotics.
Physicists tested seven deliberately odd 'silly' sprinklers to settle a long‑standing question about reverse sprinklers. The experiments debunk both Mach’s angular‑momentum balance idea and Feynman’s pressure/suction theory, showing that rotation is governed by momentum flux at the central hub where the arms meet. The results imply the reverse sprinkler behaves like an inside‑out version of a forward sprinkler, with researchers planning simulations and potential energy‑harvesting applications.
Researchers tested both standard and 'silly' sprinklers to resolve Feynman’s reverse-sprinkler puzzle. They found a reverse sprinkler does rotate in the opposite direction to a forward one, but at roughly 50 times slower. The motion arises from incoming water jets colliding off-center inside the central chamber, transferring angular momentum and producing a torque in line with momentum-flux theory; this held across varied arm shapes. The work strengthens a general framework for predicting fluid-driven rotation in turbines, pumps and energy-harvesting devices.
NYU researchers demonstrate fluid-driven gear-like coupling: two submerged rotors in a glycerol–water mix generate motion in a passive rotor via controlled liquid flows. By adjusting distance and rotation speed, the system can mimic interlocking gears (opposite directions) or belt-and-pulley systems (same direction), offering a tunable, noncontact alternative to traditional gears. Published in Physical Review Letters with NSF support.
Scientists found that simple, viscous liquids can fracture like solids when pulled beyond a 'critical stress,' with the threshold depending on stress per area rather than viscosity. The rapid fractures travel at 500–1,500 m/s—consistent with cavitation—and were observed in tar-like hydrocarbons and styrene oligomer, hinting that many liquids might exhibit this behavior and opening potential for applications in inkjet printing, soft robotics, and 3D printing.
Scientists at CERN used a rare Z-boson–tagged event to observe how a single quark traverses quark-gluon plasma, revealing fluid-like wake patterns that align with hydrodynamic predictions and confirming the primordial plasma behaved as a dense, flowing liquid in the universe’s first microseconds.
NYU researchers demonstrated a completely fluid-driven, contactless gearbox by placing two cylinders in a viscous glycerol-water mix; depending on spacing, the rotating liquid generated either opposing or same-direction motion, offering a wear-free, jam-resistant method that could revolutionize gear design and enable tunable ratios for soft robotics and distributed actuation.
NYU researchers developed a fluid-based gear system that transmits motion via directed fluid flows instead of interlocking teeth, enabling non-contact transmission and reducing wear and jam risks. Demonstrated with two submerged cylinders in a water–glycerol mix, the approach could inform soft robotics and instantly tunable gear ratios, with findings published in Physical Review Letters.
Israeli researchers at Tel Aviv University discovered that particles rotating in opposite directions within a fluid spontaneously form active, chain-like structures resembling polymers, which can move and reorganize on their own, providing insights into natural phenomena and potential applications in smart materials and microscopic robotics.
Scientists have discovered that sperm and other microorganisms use a unique form of elasticity called 'odd elasticity' in their flagella, allowing them to swim efficiently in thick fluids by bending asymmetrically and bypassing traditional physics laws like Newton's third law. This discovery, supported by mathematical modeling and high-speed microscopy, could inspire new micro-robotic designs and improve understanding of microbial movement and human health issues related to cilia function.
Germany's JUPITER supercomputer has become the world's fourth fastest, featuring advanced NVIDIA hardware and demonstrating significant energy efficiency. It facilitates groundbreaking research in fluid dynamics and simulations that benefit aerospace, medicine, and engineering, setting new standards for sustainable high-performance computing.
A recent study reveals that human sperm can defy Newton's third law of motion by utilizing non-reciprocal internal forces powered by 'odd elasticity,' enabling efficient movement through viscous environments and challenging traditional physics principles, with implications for biomedical engineering and fertility research.
New research reveals that tiny marine snow particles sink faster than larger ones due to salt absorption in stratified ocean layers, challenging traditional fluid dynamics and impacting our understanding of the ocean's role in carbon sequestration and plastic pollution distribution.
Mathematicians may have solved Hilbert's sixth problem by developing a framework that unifies microscopic particle behavior with macroscopic fluid equations, bridging a 125-year-old gap in understanding how the laws of physics operate across different scales, with potential applications in weather modeling and fluid dynamics.