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When swimming animals form cohesive groups, they can reap several benefits. Our understanding of collective animal motion has traditionally been driven by models based on phenomenological behavioral rules, but more recent work has highlighted the critical importance of hydrodynamic interactions among a group of inertial swimmers. To study how hydrodynamic interactions affect group cohesion, we develop a three-dimensional, inviscid, far-field model of a swimmer. In a group of two model swimmers, we observe several dynamical phases, including following, divergence, collision, and cohesion. Our results illustrate when cohesive groups can passively form through hydrodynamic interactions alone, and when other action is needed to maintain cohesion. We find that misalignment between swimmers makes passive cohesion less likely; nevertheless, it is possible for a cohesive group to form through passive hydrodynamic interactions alone. We also find that the geometry of swimmers critically affects the group dynamics due to its role in how swimmers sample the velocity gradient of the flow.
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http://dx.doi.org/10.1088/1748-3190/ad936d | DOI Listing |
Liver Int
October 2025
TGF-Beta and Cancer Group - Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.
Background And Aims: Hepatocellular carcinoma (HCC) has a poor prognosis and limited treatment options. TGF-β is a promising therapeutic target, but its dual role, as both a tumour suppressor and promoter, complicates its clinical application. While its effects on tumour cells are increasingly understood, its impact on the tumour stroma remains unclear.
View Article and Find Full Text PDFMed Eng Phys
October 2025
Department of Engineering Science, University of Oxford, United Kingdom. Electronic address:
Traditionally, clinical devices are designed, tested and improved through lengthy and expensive laboratory experiments and clinical trials [1]. More recently, computational methods have allowed for rapid testing, speeding up the design process and enabling far more complete searches of design space. While computational models cannot fully capture the complexities of biological systems, they provide valuable insights into crucial underlying mechanisms, such as the effects of fluid-structure interactions (FSIs).
View Article and Find Full Text PDFBioinspir Biomim
September 2025
Mechanical Engineering, University of Massachusetts Dartmouth, 285 Old Westport Road, Dartmouth, Massachusetts, 02747-2300, UNITED STATES.
Harbor seals possess a remarkable ability to detect hydrodynamic footprints left by moving objects, even long after the objects have passed, through interactions between wake flows and their uniquely shaped whiskers. While the flow-induced vibration (FIV) of harbor seal whisker models has been extensively studied, their response to unsteady wakes generated by upstream moving bodies remains poorly understood. This study investigates the wake-induced vibration (WIV) of a flexibly mounted harbor seal-inspired whisker positioned downstream of a forced-oscillating circular cylinder, simulating the hydrodynamic footprint of a moving object.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
The Biorobotics Institute, Scuola Superiore Sant'Anna, Pisa 56025, Italy.
Aquatic microorganisms typically inhabit a heterogeneous resource landscape, composed of localized and transient patches. To effectively exploit these resources, they have evolved a wide range of feeding strategies that combine chemotactic motility with active feeding flows. However, there is a notable lack of experimental studies that examine how these active flows shape resource fields to optimize feeding.
View Article and Find Full Text PDFInt J Numer Method Biomed Eng
September 2025
Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan.
The effect of shape and size of embolic agents on embolization phenomena has been discussed clinically for transcatheter arterial chemoembolization (TACE). We numerically discussed the unique embolization behavior of new deformable toroidal microparticles in blood vessels by computational fluid dynamics simulations. We employed an Eulerian-Eulerian (full Eulerian) fluid-structure interaction (FSI) method to analyze the flow and deformation behaviors of a deformable torus in a cylindrical pipe.
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