The Lagrangian coherent structures (LCSs) of simple wing cross sections in various low Reynolds number motions are extracted from high-fidelity numerical simulation data and examined in detail. The entrainment process in the wake of a translating ellipse is revealed by studying the relationship between attracting structures in the wake and upstream repelling structures, with the help of blocks of tracer particles. It is shown that a series of slender lobes in the repelling LCS project upstream from the front of the ellipse and "pull" fluid into the wake. Each lobe is paired with a corresponding wake vortex, into which the constituent fluid particles are folded. Flexible and rigid foils in flapping motion are studied, and the resulting differences in coherent structures are used to elucidate their differences in force generation. The clarity with which these flow structures are revealed, compared to the vorticity or velocity fields, provides new insight into the vortex shedding mechanisms that play an important role in unsteady aerodynamics.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.3273036 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Quantitative analysis of particle behavior constituting multiple coherent structures in liquid bridges.
J Colloid Interface Sci
January 2025
Department of Mechanical and Aerospace Engineering, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Chiba, Japan. Electronic address:
Hypothesis: Coherent structures by low-Stokes-number particles are induced within a closed flow, in which ordered flow regions known as Kolmogorov-Arnold-Moser (KAM) tori emerge. A variety of structures with different spatial characteristics has been predicted by varying the Stokes number, whereas the coexistence of structures in flow suspending various types of particles has not been hitherto demonstrated.
Experiments: Half-zone liquid bridges of O () are prepared as a closed system to induce thermocapillary-driven time-dependent flow under normal gravity conditions.
Outer hair cells stir cochlear fluids.
Elife
January 2025
Department of Mechanical Engineering, University of Rochester, Rochester, United States.
We hypothesized that active outer hair cells drive cochlear fluid circulation. The hypothesis was tested by delivering the neurotoxin, kainic acid, to the intact round window of young gerbil cochleae while monitoring auditory responses in the cochlear nucleus. Sounds presented at a modest level significantly expedited kainic acid delivery.
View Article and Find Full Text PDFDevelopment of Self-Concept in Childhood and Adolescence: How Neuroscience Can Inform Theory and Vice Versa.
Hum Dev
December 2024
Erasmus School of Social and Behavioral Sciences, Erasmus University Rotterdam, Rotterdam, The Netherlands.
How do we develop a stable and coherent self-concept in contemporary times? Susan Harter's original work, (1999; 2012), argues that cognitive and social processes are building blocks for developing a coherent sense of self, resulting in self-concept clarity across various domains in life (e.g., [pro-]social, academic, and physical).
View Article and Find Full Text PDFConvergent-beam attosecond x-ray crystallography.
Struct Dyn
January 2025
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Sub-ångström spatial resolution of electron density coupled with sub-femtosecond to few-femtosecond temporal resolution is required to directly observe the dynamics of the electronic structure of a molecule after photoinitiation or some other ultrafast perturbation, such as by soft X-rays. Meeting this challenge, pushing the field of quantum crystallography to attosecond timescales, would bring insights into how the electronic and nuclear degrees of freedom couple, enable the study of quantum coherences involved in molecular dynamics, and ultimately enable these dynamics to be controlled. Here, we propose to reach this realm by employing convergent-beam x-ray crystallography with high-power attosecond pulses from a hard-x-ray free-electron laser.
View Article and Find Full Text PDFRandom lasers (RLs) with a simple structure and low-cost properties have been recognized as an ideal analytical platform and are still challenging for liquid detecting, remaining beset for low sensitivity, complicated operation, and large analyte consumption. Here, inspired by a microfluidic sensor, a microtubule structured random laser for multifunctional sensing is demonstrated. The random laser is achieved resorting to a curly PMMA film with gain and scatterers embedded in it.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!