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Visualizzazione dei post in ordine di data per la query dissipation. Ordina per pertinenza Mostra tutti i post
Visualizzazione dei post in ordine di data per la query dissipation. Ordina per pertinenza Mostra tutti i post

martedì 29 settembre 2026

# gst: rupture dynamics of dense granular films; from liquidlike bursting to solidlike fracturing.


<< ️(AA) investigate the bursting dynamics of dense granular films punctured at imposed controlled liquid pressure. Using high-speed imaging, (They) reveal a two-stage opening process.️ At early times, the hole expands in a liquidlike manner with a nearly circular shape and a constant velocity, though significantly lower than the Taylor-Culick speed. This velocity is modeled by a balance between surface tension and effective surface viscosity, which depends on particle size and liquid depression. >>

<< ️(AA) show that as liquid pressure decreases, the initial opening slows down progressively until it ultimately reaches a jamming state. As the opening progresses, the film undergoes a transition to a solidlike regime, where faceting occurs due to fracture propagation within the granular skeleton. >>

<< ️(AA) show that the characteristic fracture size follows a 𝑡3/4 scaling, consistent with a balance between surface energy release and viscous dissipation induced by liquid redistribution within the 2D granular network. ️These findings advance (Their) understanding of the mechanics of granular films and their transition between fluidlike and solidlike behaviors. >>

Paul Gauthier, Nabil Retailleau, Yacine Khidas, et al. Rupture dynamics of dense granular films: From liquidlike bursting to solidlike fracturing. Phys. Rev. Fluids 11, 094301. Sep 8, 2026.

Also: particle, fracture, crack, drop, droplet, droploid, bubble, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, fracture, crack, drops, droplets, droploids, bubbles, transitions, fluid-particle interactions, granular fluids, granular films, granular network, bursting dynamics, surface tension, surface viscosity, viscous dissipations, jamming states, surface energy.

mercoledì 16 settembre 2026

# gst: thermodynamics of bouncing grains.


<< When a horizontal plate vibrates strongly enough, it causes small particles such as sand grains to continually bounce on it and, over time, to diffuse across its surface. This phenomenon is the cause of the well-known Chladni figure, which is drawn by a higher density of grains gathering along the nodal lines of a resonating elastic plate. >>

<< Using a heterogeneous, nonresonating plate, (AA) investigate experimentally this type of diffusion. (They) find that, for the most part, it is comparable to classical molecular diffusion. (They) can define a temperature for the bouncing grains, and the system then obeys the fluctuation-dissipation theorem. (They) also recover Maxwell-Boltzmann statistics at equilibrium, when temperature is uniform. >>

<< However, when temperature varies across the vibrating plate, the microscopic details of the grains' dynamics affect their macroscopic behavior: Fick's law, for instance, no longer applies. Instead, (Their) experiments support a new transport relation that was recently proposed to represent diffusion in Chladni's experiment. >>

<< Finally, (AA) propose an expression for the heat flux associated to the nonequilibrium steady state predicted by this new relation and test it against observations. >>

O. Devauchelle, P. Popović, P. Szymczak, et al. Thermodynamics of bouncing grains. Phys. Rev. E 114, 025420. Aug 24, 2026.
arXiv: 2606.05930v1 [cond-mat.stat-mech]. Jun 4, 2026.

Also: particles, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, particles, active brownian particles, brownian ratchet, granular materials, bouncing grains, vibrating plate, molecular diffusion, fluctuation-dissipation.

giovedì 3 settembre 2026

# gst: the ultimate state of elastic turbulence.


<< The asymptotic properties, with vanishing viscosity, of inertial turbulence in Newtonian fluids have been of intense scrutiny over the years. Much less is known about elastic turbulence - a distinct spatio-temporally chaotic state exhibited by viscoelastic fluids. >>

<< In this work, using direct numerical simulations of turbulence in a triperiodic box, (AA) show that elastic turbulence achieves an ultimate state with increasing polymer relaxation time, i.e., the Deborah number, for two different constitutive models (Oldroyd-B and FENE-P). >>

<< In the limiting state, various bulk quantities - the fluid dissipation, the polymeric energy transfer, as well as the elastic stresses - are shown to become independent of the polymer relaxation time scale, notwithstanding the microstructure deformation scales distinctly depending on the model. >>

Piyush Garg, Marco Edoardo Rosti. The ultimate state of elastic turbulence. arXiv: 2608.26479v1 [physics.flu-dyn]. Aug 27, 2026.

Also: elastic, turbulence, chaos, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, elasticity, turbulence, chaos, vanishing viscosity, inertial turbulence, elastic turbulence, elastic stress, viscoelastic fluids, polymer relaxation.

venerdì 28 agosto 2026

# gst: dissipative self-assembly of colloidal suspensions.

<< Suspensions of paramagnetic colloids exhibit kinetic arrest in strong magnetic fields. Through a dissipative process of toggling the field on and off, suspensions self-assemble into dense and dynamic steady-state phases. >>

<< (AA) construct a phase diagram using 𝑘-means clustering analysis based on domain elongation, α-shapes, contour metrics, and the degree of phase separation. (They) identify six characteristic structural regimes: a structureless phase, an arrested structure, sheets, ribbons, a spiky phase, and a transient fluid-fluid regime. >>

<< (AA) further report the distribution and alignment of domains and the generality of the results. (They) model self-assembled domain shapes using an equilibrium mean-field magnetostatic energy calculation, which predicts the surprising emergence of highly anisotropic structures driven by the sample's confinement. >>

Jason Conradt, Eric M. Furst. Dissipative self-assembly of colloidal suspensions. Phys. Rev. E 114, 025416. Aug 21, 2026.

arXiv: 2603.14637v1 [cond-mat.soft]. 

Also: dissipation, self-assembly, colloids, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, dissipation, self-assembly, colloids, anisotropic structures, steady-state phases. 

giovedì 6 agosto 2026

# gst: on the scaling of bubble interactions in dynamic turbulence; theoretical, numerical, and experimental study.

<< This (AA) study investigates dilute bubbly decaying homogeneous isotropic turbulence at high Reynolds number using theory, direct numerical simulation, and experiments. The turbulent kinetic energy and dissipation rate follow power-law decay, while the bubble population reorganizes relative to the evolving Hinze scale. When the dissipation decays sufficiently rapidly, the Hinze scale grows faster than the characteristic bubble diameter, driving the population from super-Hinze toward sub-Hinze sizes. The system passes through a mixed regime in which coalescence dominates but breakup remains active, followed by a pure-coalescence regime. Residual breakup in the mixed regime increases the number of small bubbles and enhances coalescence, leading to faster growth of the characteristic bubble size. DNS of dilute bubble-laden turbulence shows decay exponents close to single-phase turbulence and a bubble-size distribution that shifts toward smaller diameter relative to the Hinze scale. >>

<< Before the transition, the distribution exhibits two power-law ranges associated with capillary effects and inertial breakup; after the transition, it approaches a single capillary-dominated scaling. Theory and DNS predict distinct growth laws for bubble diameter in the mixed and pure-coalescence regimes, together with corresponding scalings for number density, interfacial area, and coalescence rate. These predictions are further assessed in a spatially developing pump-driven bubbly duct flow at higher Reynolds number. Despite confinement, inhomogeneity, and wall production, the measured trends agree with the theoretical and DNS-based scalings. >>

<< The (AA) results identify Hinze-scale drift as the organizing mechanism for bubble interactions in both idealized and practical decaying turbulent flows, and provide guidance for population-balance and interfacial-area-transport models. >>

Vivek Kumar, Prasoon Suchandra, Shivam Prajapati, et al. On the scaling of bubble interactions in dynamic turbulence: theoretical, numerical, and experimental study.  arXiv: 2607.25251v1 [physics.flu-dyn]. Jul 28, 2026.

Also: bubble, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, bubble, transitions, dilute bubbly decaying, coalescence, mixed- pure-coalescence regimes, dilute bubble-laden turbulence, capillary effects, inertial breakup, decaying turbulent flows.  

martedì 7 luglio 2026

# gst: apropos of avalanche propagations (e.g. large cascades), sandpile models on complex networks.


<< ️(AA) investigate the sandpile model on complex networks by developing a branching-process framework that explicitly incorporates dissipation during avalanche propagation. Unlike classical branching descriptions, which assume conservative transport and locally tree-like independence, the present approach introduces grain-loss effects directly into the offspring distribution, yielding generalized generating functions for dissipative avalanche dynamics. >>

<< ️In the dissipative regime, avalanche-size distributions acquire exponential cutoffs while preserving topology-dependent scaling behavior. Numerical simulations confirm the theoretical predictions on sparse random networks and reveal systematic deviations in highly structured topologies. In particular, by using Holme-Kim clustered scale-free networks, (They) show that increasing clustering continuously lowers the avalanche exponent and enhances the probability of large cascades, demonstrating that short cycles generate strong correlations that invalidate the classical independent-branch approx imation. >>

<< ️Surprisingly, trees also exhibit substantial deviations from power-law because low edge density and the abundance of leaves constrain avalanche propagation. These results show that dissipation, clustering, and sparse connectivity fundamentally reshape avalanche size distribution of the sandpile model on networks and establish quantitative limits for branching-process descriptions of avalanche dynamics. >>

Komlan Fiagbe, Jean-François de Kemmeter, Timoteo Carletti. Sandpile Models on complex networks. arXiv: 2607.02023v1 [cond-mat.stat-mech]. Jul 2, 2026.

Also: network, dissipation, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, network, dissipation, sandpile, branching-process framework, avalanche propagation, grain-loss effects, dissipative avalanche dynamics, sparse random networks, clustering, sparse connectivity.

martedì 23 giugno 2026

# gst: on the geometry of spreading puddles.


<< ️(AA) develop a geometric model for the spreading of shallow, viscous puddles of arbitrary shape, building on the recent 'capillary current' model for axisymmetric droplets. In short, (They) assume that a spreading puddle remains close to instantaneous mechanical equilibrium as it spreads, with hydrostatic pressure balanced by surface curvature. In turn, its contact line advances so as to maximize the rate of energy loss subject to viscous dissipation. >>

<< ️The resulting system yields a natural geometric evolution equation for both the two-dimensional footprint and the three-dimensional depth profile of a spreading puddle. In appropriate limits, it recovers the classical spreading laws for axisymmetric droplets, a local version of the Hoffman-Voinov-Tanner law for small non-axisymmetric puddles, and a nonlocal Hele-Shaw-like description for large, relatively regular puddles. >>

David Darrow. On the Geometry of Spreading Puddles. arXiv: 2606.13893v1 [physics.flu-dyn]. Jun 11, 2026.

Also: drop, droplet, droploid, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, drops, droplets, droploids, spreading puddle, axisymmetric droplets, surface curvature, viscous dissipation.

lunedì 22 giugno 2026

# gst: dissipation-coherence tradeoff for stochastic oscillations.


<< ️Autonomous noisy oscillations in biochemical and mesoscopic systems require nonequilibrium driving and therefore dissipation. A striking conjecture by Oberreiter, Barato, and Seifert (OBS) proposes a universal lower bound on the entropy produced per oscillation period in terms of the coherence number of the slowest oscillatory mode (L. Oberreiter et al. [Phys. Rev. E 106, 014106 (2022)]). >>

<< ️Here (AA) derive a weaker but rigorous lower bound that preserves the OBS structure while introducing a mode-uniformity factor that quantifies how evenly the oscillatory eigenmode is distributed across states in the steady-state inner product. The result makes explicit that an eigenvalue-only prefactor can fail when the dominant oscillatory mode is localized. >>

<< ️(They) also outline a proof-of-principle route for estimating this factor from low-dimensional data under single-mode dominance and sufficiently informative measurements, and derive an eigenvector-free corollary using only the smallest stationary probability. >>

<< ️Translation-invariant Markov jump processes on a ring provide a symmetry-protected class with 𝜂=1, so the refinement reduces to the OBS form; the drift-diffusion limit on a circle saturates the bound. >>

Jie Gu. Dissipation-coherence tradeoff for stochastic oscillations. Phys. Rev. E 113, 064130.  Jun 15, 2026.
arXiv: 2606.05498v1 [cond-mat.stat-mech]. Jun 3, 2026.

Also: noise, disorder, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, noise, disorder, dissipation, entropy, stochasticity, stochastic processes, autonomous noisy oscillations, stochastic oscillations, disorder-induced localization, time series analysis, transitions.

martedì 26 maggio 2026

# gst: formation of mechanical rogue waves.

<< ️Rogue waves, characterized by their abrupt and extreme localization in space and time, have evolved from maritime folklore to subjects of intense study across diverse fields, from hydrodynamics and nonlinear optics to plasmas and condensed matter physics. In mechanical systems, however, experimental realization remains elusive despite theoretical and numerical predictions. This gap stems from the stringent requirements for controllable nonlinearity, the high-fidelity initialization of the system, and the necessity to overcome inherent energy dissipation. >>

<< ️Here, (AA) report the experimental formation of mechanical rogue waves in a precisely engineered one-dimensional metamaterial lattice with tailored nonlinearity and minimal dissipative losses. Using a precision electromagnetic release system, (They) prescribe initial strain profiles that trigger a transition from dispersive decay to extreme wave focusing. >>

<< ️(Their) parametric analysis reveals that the emergence of these extreme events is strictly contingent upon a synergy between high nonlinearity and a broad spatial energy reservoir within the initial seed. Crucially, neither factor alone is sufficient to overcome dispersion and trigger the observed focusing. >> 

<< ️These findings establish a robust platform for studying transient nonlinear wave focusing phenomena in mechanical systems and offer insights for harnessing extreme wave localization for applications such as energy harvesting, waveguiding, and mechanical signal processing. >>

Yasuhiro Miyazawa, Christopher Chong, Panayotis G. Kevrekidis, et al. Formation of mechanical rogue waves. arXiv: 2605.18518v1 [nlin.PS]. May 18, 2026.

Also: waves, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, rogue waves, mechanical rogue waves, transitions.

giovedì 14 maggio 2026

# gst: apropos of dissipation of fast tides, turbulent damping of fast tidal oscillations by three-dimensional Rayleigh-Bénard convection with a radiating free surface.

<< ️(AA) present three-dimensional Dedalus simulations of Rayleigh–Benard convection with a blackbody-radiating free upper surface, subject to a low-amplitude oscillatory forcing that mimics tidal perturbations in convective envelopes of stars and planets. The forcing period is 10–100 times shorter than the convective timescale, tconv. Using a Reynolds decomposition of the velocity field averaged over one oscillation period, in which the tidal oscillations naturally constitute the fluctuating field and xconvection the mean flow, (They) elucidate the kinetic energy exchange between the two. >>

<< ️Provided the oscillatory Reynolds number exceeds a modest threshold, (They) find that the oscillations systematically transfer kinetic energy to the mean flow at a volume-averaged rate D_R∼u′^(2)t^−1_conv, where u′ is the rms fluctuation velocity. This reflects strong, order-unity correlations between the fluctuation velocities and the mean flow. These arise because the oscillatory forcing displaces fluid elements that are then redirected by buoyancy and incompressibility in the same manner as the mean flow. >>

<< The transfer is dominated by correlations involving vertical velocity fluctuations and vertical gradients of the mean flow. The resulting energy transfer rate is consistent, within the equilibrium-tide framework, with the observed tidal circularisation of solar-type binaries and with the orbital evolution of moons of Jupiter and Saturn. This validates the formalism proposed by Terquem (2021) for the dissipation of fast tides, a longstanding problem. Replacing the free surface with a rigid upper boundary significantly and artificially modifies the correlations. >>

Caroline Terquem, Alexander Boone, Enrico Martinez. Turbulent damping of fast tidal oscillations by three-dimensional Rayleigh-Bénard convection with a radiating free surface. arXiv: 2605.05108v1 [astro-ph.SR]. May 6, 2026.

Also: turbulence, fluctuations, dissipation,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, fluctuations, dissipation, turbulent damping, tidal oscillations, tidal perturbations, Rayleigh-Bénard convection, dissipation of fast tides.

venerdì 8 maggio 2026

# gst: capillary slinky; equilibrium and dynamics of a droplet in a soft spring.


<< ️Springs can be found in many applications and biological systems, and when these are soft, they easily deform. At small scales, capillarity can induce a force leading to spring deformations when the elastocapillary number is small. >>

<< ️ (AA) demonstrate through experiments the nontrivial equilibrium-shape liquid droplets adopt in these soft springs, which form an annulus, eruciform, and spherical shapes. When these droplets are set in motion, they display different flow regimes with significant dissipation generated by the internal rotational flow. >>

<< ️The static and dynamics of droplets in such a capillary slinky are also used to demonstrate how surface tension can actuate springs by stretching/compression, while providing a way for active flow control in soft springs. >>

Bidisha Bhatt, Andreas Carlson. Capillary slinky: Equilibrium and dynamics of a droplet in a soft spring. Phys. Rev. Fluids 11, 043607. Apr 29, 2026.

Also: drop, droplet, droploid, bubble, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, drops, droplets, droploids, capillarity, capillary slinky, spring deformations, annulus, eruciform, spherical shapes, rotational flows.

sabato 28 marzo 2026

# gst: apropos of different degrees of decimation, reduction of triadic interactions suppresses intermittency and anomalous dissipation in turbulence.

<< ️(AA) investigate how the defining statistical features of three-dimensional turbulence respond to systematic reductions of the Fourier-space triadic interaction network. Using direct numerical simulations of both fractally and homogeneously decimated Navier-Stokes dynamics, (They) show that progressive thinning of the set of active modes leads to a systematic suppression of intermittency and, most strikingly, to the vanishing of the mean dissipation rate in the large-Reynolds-number limit. >>

<< ️Structure-function exponents collapse onto their dimensional values, the multifractal singularity spectrum contracts, and the analyticity width extracted from the exponential spectral tail increases monotonically with decimation-each indicating a substantial regularization of the velocity field. >>

<< ️Together, these results provide direct evidence that anomalous dissipation in incompressible turbulence is not a generic property of the Navier-Stokes equations, but instead requires the full combinatorial richness of their triadic nonlinear interactions. >>

Anikat Kankaria, Ritwik Mukherjee, Sugan Durai Murugan, et al. Reduction of triadic interactions suppresses intermittency and anomalous dissipation in turbulence. arXiv: 2603.19180v1 [physics.flu-dyn]. Mar 19, 2026.

Also: turbulence, intermittency, dissipation, singularity, collapse, transition, network, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, three-dimensional turbulence, incompressible turbulence, intermittency, dissipation, anomalous dissipation, singularity, multifractal singularity spectrum contracts, collapse, transitions, networks, triadic interactions, progressive thinning, decimation.

mercoledì 10 dicembre 2025

# gst: degrees of universality in wave turbulence

<< ️Turbulence of weakly interacting waves displays a great deal of universality: independence of the details of the interaction and of the pumping and dissipation scales. Here (AA) study how inverse turbulent cascades (from small to large scales) transition from weak to strong. (They) find that while one-loop corrections can be dependent on excitation and dissipation scales, new types of universality appear in strong turbulence. (They) contrast turbulence of spin waves in ferromagnets with turbulent cascades in the Nonlinear Schrödinger Equation (NSE) and in an MMT-like (Majda-McLaughlin-Tabak) model in higher dimensions having a multiplicative interaction vertex: vertex renormalization gives rise to dependence on the pumping (UV scale) in the former but not in the latter. >>

<< ️As a result of this spectral nonlocality, spin-wave turbulence stops being weak if one is sufficiently far from the pumping scale, even when the interaction of waves with comparable wavenumbers is weak. (AA) paraphrase this as: nonlocality enhances nonlinearity. >>

<< ️(AA) then describe strong turbulence in a multi-component version of these models with a large number of components. (They) argue that strong spin-wave turbulence is similar to turbulence of the focusing NSE, as it realizes a critical-balance state. However, UV nonlocality causes the level of spin-wave turbulence at large scales to decrease with increasing pumping level, culminating in a state that is independent of the level of pumping. >>

Jiasheng Liu, Vladimir Rosenhaus, Gregory Falkovich. Degrees of universality in wave turbulence. arXiv: 2512.04866v1 [cond-mat.stat-mech]. Dec 4, 2025.

Also: waves, turbulence, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, waves, turbulence, transitions.

giovedì 6 novembre 2025

# gst: a probability space at inception of stochastic process.

<< ️Recently, progress has been made in the theory of turbulence, which provides a framework on how a deterministic process changes to a stochastic one owing to the change in thermodynamic states. It is well known that, in the framework of Newtonian mechanics, motions are dissipative; however, when subjected to periodic motion, a system can produce nondissipative motions intermittently and subject to resonance. It is in resonance that turbulence occurs in fluid flow, solid vibration, thermal transport, etc. In this, the findings from these physical systems are analyzed in the framework of statistics with their own probability space to establish their compliance to the stochastic process. >>

<< ️In particular, a systematic alignment of the inception of the stochastic process with the signed measure theory, signed probability space, and stochastic process was investigated. It was found that the oscillatory load from the dissipative state excited the system and resulted in a quasi-periodic probability density function with the negative probability regimes. In addition, the vectorial nature of the random velocity splits the probability density function along both the positive and negative axes with slight asymmetricity. By assuming that a deterministic process has a probability of 1, (AA) can express the inception of a stochastic process, and the subsequent benefit is that a dynamic fractal falls on the probability density function. Moreover, (They) leave some questions of inconsistency between the physical system and the measurement theory for future investigation. >>

Liteng Yang, Yuliang Liu, et al. A Probability Space at Inception of Stochastic Process. arXiv: 2510.20824v1 [nlin.CD]. Oct 8, 2025.

Also: turbulence, dissipation, intermittency, random, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, dissipation, intermittency, randomness, transitions.

lunedì 15 settembre 2025

# gst: dual role for heterogeneity in dynamic fracture.


<< ️(AA) approach the problem of heterogeneous dynamic fracture by considering spatiotemporal perturbations to planar crack fronts. Front propagation is governed by local energy balance between the elastic energy per unit area available to fracture 𝐺 and the dissipation in creating new surfaces. 𝐺 is known analytically as a perturbation series in the crack front fluctuation. >>

<< ️For dissipation that monotonically increases with the crack speed, (AA) derive an equation of motion for crack fronts that is second-order accurate. In the linear order, heterogeneity does not change the net speed of fracture. In the second order, nonlinear interactions of the front and the heterogeneous landscape populate an intermediate-scale fluctuation spectrum. >>

<< ️(AA) find that, when dissipation weakly grows with velocity, nonlinearities globally amplify dissipation and reduce the crack speed. Strong velocity dependence, however, mitigates toughening effects and may facilitate fracture. >>

Itamar Kolvin, Mokhtar Adda-Bedia, Dual Role for Heterogeneity in Dynamic Fracture. Phys. Rev. Lett. 135, 106201. Sep 3, 2025.

arXiv: 2407.02347v1 [cond-mat.mtrl-sci]. Jul 2,  2024.

Also: fracture, crack, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, fracture, crack, front propagation

martedì 2 settembre 2025

# gst: dynamics and frictional dissipation for treading slowly in a puddle.

<< ️The process of producing a liquid column is common in daily life and industrial applications, such as walking through a puddle and roller printing. While governed by the Navier-Stokes equation, its dynamics are often studied by numerical means, which hinders a full understanding of the rich mixture of physics behind, for instance, the competition of surface and potential energies, and how the pinch off is affected by the kinetic energy and water jet when a large cylinder is used. For pedestrians rushing out of the rain, the water column inevitably involves turbulence and defies simple theoretical analyses.  >>

<< ️As a result, this (AA) work will focus only on cases with a low Reynolds number to enable laminar flow and the existence of reversible and quasistatic stages. Combined with simple models, (They) elucidate the mechanism that drives the change of morphology and derive analytic expressions for the critical height and upper radius for the liquid column when transiting between three stages. >>

<< ️Stage I is characterized by a static and reversible profile for the column whose upper radius 𝑟𝑡 equals that of the cylinder. The column becomes irreversible and 𝑟𝑡 starts shrinking upon entering stage II. It is not until 𝑟𝑡 stops shrinking that the column neck accelerates its contraction and descends toward the pool, the quantitative behavior of which is among the successful predictions of our theory. Pinch off dominates the second half of stage III without its usual signature of self-similarity. This is discussed and explained with an interesting incident involving a water jet similar to that made by a dropping stone. >>

Chung-Hao Chen, Zong-Rou Jiang, Tzay-Ming Hong. Dynamics and frictional dissipation for treading slowly in a puddle. Phys. Rev. E 112, 025105. Aug 25, 2025.

arXiv: 2310.09737v2 [physics.flu-dyn]. May 18, 2024.

Also: walk, walking, in https://www.inkgmr.net/kwrds.html 

Keywords: walk, walking.

venerdì 6 giugno 2025

# gst: symmetry breaking in time-dependent billiards.

AA << investigate symmetry breaking in a time-dependent billiard that undergoes a continuous phase transition when dissipation is introduced. The system presents unlimited velocity, and thus energy growth for the conservative dynamics. When inelastic collisions are introduced between the particle and the boundary, the velocity reaches a plateau after the crossover iteration. The system presents the expected behavior for this type of transition, including scale invariance, critical exponents related by scaling laws, and an order parameter approaching zero in the crossover iteration. >>

AA << analyze the velocity spectrum and its averages for dissipative and conservative dynamics. The transition point in velocity behavior caused by the physical limit of the boundary velocity and by the introduced dissipation coincides with the crossover interaction obtained from the Vrms (root mean sq V) curves. Additionally, (they) examine the velocity distributions, which lose their symmetry once the particle's velocity approaches the lower limit imposed by the boundary's motion and the system's control parameters. This distribution is also characterized analytically by an expression P(V,n), which attains a stationary state, with a well-defined upper bound, only in the dissipative case. >>

Anne Kétri Pasquinelli da Fonseca, Edson Denis Leonel. Symmetry breaking in time-dependent billiards. arXiv: 2505.20488v1 [nlin.CD]. May 26, 2025.

Also: billiard, transition, dissipation,  in https://www.inkgmr.net/kwrds.html 

Keywords: gst, billiard, particles, transitions, dissipation, symmetry breaking, inelastic collisions.

venerdì 23 maggio 2025

# gst: toy model of turbulent shear flow using vortons.

AA << introduce a toy model for shear flows, exploiting the spatial intermittency and the scale separation between large-scale flows and small-scale structures. The model is highly sparse, focusing exclusively on the most intense structures, which are represented by vortons—dynamically regularized quasisingularities that experience rapid distortion from the large-scale shear. The vortons, in turn, influence the large-scale flow through the subgrid stress tensor. >>

<< Despite its simplicity, the model displays an interesting transition between two distinct regimes: (i) a laminar regime, where dissipation is entirely attributed to the large-scale flow and the vortons dynamics is essentially diffusive, and (ii) a turbulent regime, in which most of the dissipation arises from the vortons. These regimes correspond to different scalings of dissipation and the Grashof number as functions of the Reynolds number, with power-law relationships that resemble those observed in classical turbulence. >>

Wandrille Ruffenach, Lucas Fery, Bérengère Dubrulle. Toy model of turbulent shear flow using vortons. Phys. Rev. Fluids 10, 054601. May 1, 2025.

arXiv:2501.05779v2 [physics.flu-dyn]. 

Also: turbulence, intermittency, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, intermittency, transitions, vortons

venerdì 7 marzo 2025

# gst: transition to inverse cascade in turbulent rotating convection in absence of the large-scale vortex.


<< Turbulent convection under strong rotation can develop an inverse cascade of kinetic energy from smaller to larger scales. In the absence of an effective dissipation mechanism at the large scales, this leads to the pile-up of kinetic energy at the largest available scale, yielding a system-wide large-scale vortex (LSV). Earlier works have shown that the transition into this state is abrupt and discontinuous. >>

Here, AA << study the transition to the inverse cascade in the case where the inverse energy flux is dissipated before it reaches the system scale, suppressing the LSV formation. (They) demonstrate how this can be achieved in direct numerical simulations by using an adapted form of hypoviscosity on the horizontal manifold. (They) find that in the absence of the LSV, the transition to the inverse cascade becomes continuous. This shows that it is the interaction between the LSV and the background turbulence that is responsible for the observed discontinuity. >>

AA << furthermore show that the inverse cascade in absence of the LSV has a more local signature compared to the case with LSV. >>️

Xander M. de Wit. Transition to inverse cascade in turbulent rotating convection in absence of the large-scale vortex. arXiv: 2502.16275v1 [physics.flu-dyn]. Feb 22, 2025. 

Also: turbulence, dissipation, transition, vortex, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, turbulence, dissipation, transitions, vortices


lunedì 24 febbraio 2025

# gst: when homogeneous systems meet dissipation and disorder.

AA << investigate the localization and topological properties of the non-equilibrium steady state (NESS) in a one-dimensional homogeneous system. (Their) results demonstrate that, despite the absence of disorder in the initial system, the NESS can exhibit localization under bond dissipation. >>

<< Conversely, for an initially flat-band system with compactly localized wave functions, the NESS is delocalized. >>

<< Furthermore, (They) find that the initial localization characteristics of the system significantly influence the localization properties of the NESS. Drawing upon the concept of Bose-Einstein condensate broadening in cold-atom experiments, along with experimental data, (AA) systematically characterize the impact of disorder on the localization and topological properties of the NESS. >>

<< The phase diagram reveals that the NESS can be topologically non-trivial even when the initial state is topologically trivial, and that the topological triviality of the initial state weakens the topological non-triviality of the NESS. >>

Xixi Feng, Ao Zhou, et al. When Homogeneous Systems Meet Dissipation and Disorder. arXiv: 2502.11383v1 [cond-mat.dis-nn]. Feb 17, 2025. 

Also: order, disorder, disorder & fluctuations, transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, order, disorder, disorder & fluctuations, transitions