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In vivo measurement of blood clot mechanics from computational fluid dynamics based on intravital microscopy images
摘要： Ischemia which leads to heart attacks and strokes is one of the major causes of death in the world. Whether an occlusion occurs or not depends on the ability of a growing thrombus to resist flow forces exerted on its structure. This manuscript provides the first known in vivo measurement of how much stress a clot can withstand, before yielding to the surrounding blood flow. Namely, Lattice-Boltzmann Method flow simulations are performed based on 3D clot geometries, which are estimated from intravital microscopy images of laser-induced injuries in cremaster microvasculature of live mice. In addition to reporting the blood clot yield stresses, we also show that the thrombus 'core' does not experience significant deformation, while its 'shell' does. This indicates that the shell is more prone to embolization. Therefore, drugs should be designed to target the shell selectively, while leaving the core intact to minimize excessive bleeding. Finally, we laid down a foundation for a nondimensionalization procedure which unraveled a relationship between clot mechanics and biology. Hence, the proposed framework could ultimately lead to a unified theory of thrombogenesis, capable of explaining all clotting events. Thus, the findings presented herein will be beneficial to the understanding and treatment of heart attacks, strokes and hemophilia.
关键词： Yielding,Blood,Simulation,Microscopy,Thrombus,Lattice Boltzmann Method
更新于2025-09-23 15:22:29
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Simulation of laser-produced single cavitation bubbles with hybrid thermal Lattice Boltzmann method
摘要： Using a hybrid thermal Lattice Boltzmann method, the dynamics of laser-produced single cavitation bubbles in bulk liquid and the bubble collapse process near a solid boundary are numerically investigated. The simulated bubble evolutions satisfyingly agree with the theoretical calculations and the previous experimental results. The simulated bubble radius changes in bulk liquid are in good accordance with the calculations of a revised 2-D Rayleigh–Plesset equation that incorporates an extra thermal effect term. The maximum bubble radius is linearly proportional to the bubble collapse time and the input laser energy, which is consistent with the experimental data and bubble dynamics theory. Processes of a single cavitation bubble collapse at various distances from a solid boundary are analyzed in detail. The velocity vectors, density, pressure, and temperature fields are presented. The retarding effect of a solid boundary is successfully reproduced in the LBM simulations and leads to bubble elongation, the formation of micro-jet, bubble toroidal deformation, and the attraction of the bubble to the boundary during the collapse phase. The attraction effect, maximum jet velocity, and maximum pressure at the solid boundary all increase with reduced non-dimensional distance. A critical non-dimensional distance of 2.2 is validated by both the simulation and experiment. The hybrid thermal Lattice Boltzmann method is a reliable tool to investigate non-isothermal cavitation bubble dynamics.
关键词： Thermal Lattice Boltzmann method,Bubble collapse near boundary,Laser-produced bubble,Cavitation bubble dynamics
更新于2025-09-11 14:15:04
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Fully resolved simulation of single-particle dynamics in a microcavity
摘要： Fluid flow laden with a single finite size neutrally buoyant particle over a confined microcavity adjacent to a main straight microchannel is numerically simulated by a fully resolved simulation method. This method is based on coupled immersed boundary–lattice Boltzmann method, which can directly resolve the fluid flow and the interactions between fluid and particles without any empirical models. The evolution of the fluid microvortex and the motions of the particle, such as trapping, orbiting, and rotating, in a confined microcavity are investigated as a function of Reynolds number ranging from 5 to 250. The results reveal that the topology structure of the microvortex changes from local apex ear, to globally crescentic and then triangle as Reynolds number increases. Three phases for particle stable and unstable entrapping behavior and four particle-trapping modes are observed and identified. The particle-trapping pathway varies from outer to inner, invariable, inner to outer, and inner to escape corresponding to different Reynolds numbers. The mechanisms for this phenomenon are revealed by a new improved competing model between outward centrifugal force and inward inertial lift force. Finally, the orbiting and rotating motion of the particle is quantitatively analyzed for the first time.
关键词： Lattice Boltzmann method,Immersed boundary method,Particle trapping,Microvortex
更新于2025-09-10 09:29:36