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Investigation of microbubble motion in a microvessel with various obstructions filled with viscous fluid: A finite element modeling study

Authors :

Mahdi Mirzaei¹ Afsaneh Mojra²

1- دانشگاه صنعتی خواجه نصیرالدین طوسی 2- دانشگاه صنعتی خواجه نصیرالدین طوسی

Keywords :

Microbubbles،vessel،Computational Simulation،Shear stress

Abstract :

Microbubbles have emerged as powerful agents in biomedical imaging, targeted drug delivery, and ultrasound-mediated therapies due to their unique acoustic and transport properties. However, their motion within microvessels containing irregular structures remains insufficiently understood, particularly under viscous flow conditions where hydrodynamic and surface tension forces compete. Finite element modeling in COMSOL Multiphysics was used to analyze microbubble dynamics in viscous microvessels. Also, the Rayleigh–Plesset equation was applied to study microbubbles, capturing their radius dynamics under pressure, surface tension, and viscosity. The results reveal that obstruction geometry and position significantly influence microbubble trajectories and deformation, with asymmetrical obstructions inducing lateral migration. Changes in horizontal radius had little effect on bubble morphology. Shear stress analysis showed no consistent trend with vertical radius but indicated a clear increase with larger horizontal radii, where a threefold radius increase nearly doubled the maximum shear stress. During 4 microsecond interval period, the microbubble exhibits oscillatory behavior with a maximum radial displacement of approximately 0.4 µm. These findings provide new mechanistic insights into microbubble–obstruction interactions, supporting the optimization of microbubble-mediated therapies and microfluidic biomedical device design.