In this work we investigate the dynamics of inertial particles using finite-time Lyapunov exponents (FTLE). In particular, we characterize the attractor and repeller structures underlying preferential concentration of inertial particles in terms of FTLE fields of the underlying carrier fluid. Inertial particles that are heavier than the ambient fluid (aerosols) attract onto ridges of the negative-time fluid FTLE. This negative-time FTLE ridge becomes a repeller for particles that are lighter than the carrier fluid (bubbles). We also examine the inertial FTLE (iFTLE) determined by the trajectories of inertial particles evolved using the Maxey-Riley equations with nonzero Stokes number and density ratio. Finally, we explore the low-pass filtering effect of Stokes number. These ideas are demonstrated on two-dimensional numerical simulations of the unsteady double-gyre flow.
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http://dx.doi.org/10.1103/PhysRevE.93.033108 | DOI Listing |
Sci Rep
January 2025
Zhejiang University of Water Resources and Electric Power, Hangzhou, 310018, P. R. China.
The working performance of the discrete functional surface is affected by the surface form. Both the surface form and the geometric function should be considered in tolerance design. However, the tolerance of different parts has different influence on the geometric function and surface form.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
Department of Mechanical and Manufacturing Engineering, Schulich School of Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada.
This study investigates the movements of particles in an accelerated toroidal flow channel filled with water, with specific applications for a particle imaging velocimetry gyroscope (PIVG). We used computational fluid dynamics (CFD) to simulate particle behavior under different angular accelerations. These angular accelerations were 4 rad/s, 6 rad/s, and 8 rad/s for particles densities of 1100 kg/m, 1050 kg/m, and 980 kg/m.
View Article and Find Full Text PDFSci Bull (Beijing)
December 2024
Key Laboratory for Laser Plasmas and Department of Physics and Astronomy, Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China; Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. Electronic address:
Although ignition had been achieved at the National Ignition Facility (NIF), recent observations of the experiments indicate novel physics that beyond theoretical predictions emerge, e.g., the neutron analysis of experiments has revealed deviations from the Maxwellian distributions in ion relative kinetic energies of burning plasmas, with the surprising emergence of supra-thermal deuterium and tritium (DT) ions that fall outside the predictions of macroscopic statistical hydrodynamic models.
View Article and Find Full Text PDFPhys Rev E
November 2024
School of Mathematics, University of Warwick, United Kingdom.
In this paper, we introduce a computational technique for modeling heterogeneous thermoresponsive hydrogels. The model resolves local fluid-solid interactions in hydrogel pores during the deswelling process. The model is a Lagrangian particle-based technique, which benefits from computational grids that represent polymer beads inside hydrogel scaffolds.
View Article and Find Full Text PDFPhys Rev E
November 2024
Ecole Nationale Supérieure de Génie Mathématique et Modélisation (ENSGMM), Université Nationale des Sciences, Technologies, Ingénierie et Mathématiques, Abomey, Republique du Bénin.
On applying a small bias force, nonequilibrium systems may respond in paradoxical ways such as with giant negative mobility (GNM)-a large net drift opposite to the applied bias, or giant positive mobility (GPM)-an anomalously large drift in the same direction as the applied bias. Such behaviors have been extensively studied in idealized models of externally driven passive inertial particles. Here, we consider a minimal model of a memory-driven active particle inspired from experiments with walking and superwalking droplets, whose equation of motion maps to the celebrated Lorenz system.
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