Numerical modeling of inertial microcavitation for fluid-structure interactions and soft matter rheometry
- Sponsor
- Mechanical Science and Engineering
- Speaker
- Professor Mauro Rodriguez, School of Engineering, Brown University
- Contact
- Amy Rumsey
- rumsey@illinois.edu
- Phone
- 217-300-4310
- Originating Calendar
- MechSE Seminars
Abstract
Understanding the bubble dynamics and material response interactions is critical to predicting, enhancing or mitigating damage of soft tissues in biomedical applications (e.g., focused ultrasound therapies). Recent advancements have enabled the mechanical property characterization of soft (tissue-like) materials using spherical microbubbles in the high strain rate regime (i.e., 103/s to 108/s). This seminar will present our recent numerical modeling developments to: (i) characterize soft tissues via the Inertial Microcavitation Rheometry (IMR) technique [Estrada et al. J. Mech. Phys. Solids, 2018] and (ii) understand the fluid-structure interaction dynamics of a nonspherical inertial microbubble collapse at a gel-water interface.
IMR compares bubble radius histories from numerical simulations and laser-induced cavitation (LIC) experiments for soft material rheometry of hydrogels. We have accelerated the IMR characterization procedure from hours to seconds by using a modified Rayleigh collapse time derived from an energy analysis approach. We show that the augmented collapse time accounts for surface tension, weak compressibility, and linear viscoelastic constitutive models. The method has been further advanced to use a Bayesian inference model selection approach. We obtained agreement between theory, numerical simulations, and LIC experimental data for water and various hydrogels.
Soft tissues are typically multi-material environments (e.g., muscle tissue) in which inertially collapsing microbubbles become nonspherical. The modeling and experimental observation of this fluid-structure interaction is challenging and poorly understood and beyond the capabilities of IMR. We will present our study of a simplified geometry involving an inertially collapsing microbubble at a hydrogel-water interface. We leverage the open-source Multi-component Flow Code [Radhakrishnan & Le Berre et al. Comp. Phys. Comm. 2024)] which solves the compressible flow equations using a 6-equation multiphase model with a phase change and hyperelasticity model for compressible materials. We will show the agreement of the strains and velocity contours and wave propagation speeds between our simulations and LIC experiments. Future directions and applications for numerically simulating multi-component flows involving finite deformations in and near viscoelastic materials will also be presented.
About the Speaker
Mauro Rodriguez Jr. is an Assistant Professor of Engineering in the School of Engineering at Brown University, where he joined the faculty in 2021. He earned his B.S. degree with honors from the University of Illinois at Urbana-Champaign in 2010, his M.S from Stanford University in 2012, and his Ph.D. from the University of Michigan, Ann Arbor in 2018, all in Mechanical Engineering. His dissertation focused on high-fidelity computational simulations of bubble dynamics near (linear) viscoelastic media. Prior to joining Brown, he was a postdoctoral research fellow at the California Institute of Technology. Rodriguez’s current research interests are in cavitation bubble dynamics in and near viscoelastic materials. He uses high-fidelity computational fluid dynamics to study wave and bubble dynamics in and near hard/soft materials relevant to energy science, naval engineering, and biomedicine applications.
Host: Professor Arne Pearlstein