Category: Publications

Mike Lee’s paper with Robert Hunt and others, Bioprosthetic aortic valve diameter and thickness are directly related to leaflet fluttering: Results from a combined experimental and computational modeling study, has been accepted to appear in JTCVS Open, the open-access mirror of the Journal of Thoracic and Cardiovascular Surgery. This study demonstrates that bioprosthetic heart valves with smaller diameters and/or thicker leaflets generate higher fluttering frequencies in experimental and computational pulse duplicators. Because fluttering can impair the durability of flexible structures, extensions of this work may ultimately lead to new device design targets or selection guidelines to improve the durability of valve replacement.

Congratulations, Mike!

Jianhua Qin’s paper with Amin, An immersed interface-lattice Boltzmann method for fluid-structure interaction, has been accepted to appear in Journal of Computational Physics. (A preprint is available on the arXiv.) This paper develops what is, so far as we know, the first extension of the immersed interface method to lattice Boltzmann method-based descriptions of fluid flows.

Congratulations, Jianhua!

Ben Vadala-Roth’s paper, Stabilization Approaches for the Hyperelastic Immersed Boundary Method for Problems of Large-Deformation Incompressible Elasticity, has been accepted to appear in Computer Methods in Applied Mechanics and Engineering. (A preprint is available on the arXiv.) This paper proposes a simple stabilization that resembles approaches from nearly incompressible solid mechanics to improve the volume conservation of the immersed finite element method, as demonstrated by its performance in widely used benchmark problems of incompressible hyperelasticity adapted from the solid mechanics literature, along with fully dynamic FSI applications, including a large-scale model of esophageal transport.

Congratulations, Ben!

Charles Puelz’s paper, A Sharp Interface Method for an Immersed Viscoelastic Solid, has been accepted to appear in Journal of Computational Physics. (A preprint is available on the arXiv.) This paper develops an extension of the hyperelastic immersed boundary method that sharply resolves pressure discontinuities at fluid-structure interfaces by modifying the definition of the elastic stress tensor associated with the hyperelastic material response. Unlike most other sharp-interface immersed boundary methods, however, this approach allows us to use standard discretization methods that are “oblivious” to the presence of the pressure discontinuity. Numerical tests show the impact of the method on the accuracy of the overall scheme, and an approach is developed that allows us to compute the splitting efficiently.

Congratulations, Charles!

Mike’s paper, Fluid-Structure Interaction Models of Bioprosthetic Heart Valve Dynamics in an Experimental Pulse Duplicator, has been accepted to appear in Annals of Biomedical Engineering. (A preprint is available on engrXiv.) This paper uses IBAMR’s version of the immersed finite element method to simulate the dynamics of bioprosthetic heart valves (BHVs) in the aortic test section of experimental pulse duplicator systems. An initial experimental validation of the models is demonstrated through comparisons to data on pressures, flow rates, and leaflet kinematics. The paper also contrasts the flow patterns and leaflet strains and stresses generated by porcine tissue and bovine pericardial BHVs, and demonstrates the ability of the model to capture the large scale flow features.

Congratulations, Mike!

Our review paper with Neelesh Patankar (Northwestern) on immersed approaches to fluid-structure interaction is now in press at Annual Review of Fluid Mechanics.

Amin Kolahdouz’s paper, An immersed interface method for discrete surfaces, has been accepted to appear in the Journal of Computational Physics. (A preprint is available on the arXiv.) This paper develops an extension of the immersed interface method (IIM) that is specialized to discrete surface representations, such as triangulated surfaces. It also establishes through extensive numerical examples that IIMs that use only the lowest-order jump conditions (for the pressure and viscous shear stress) at immersed interfaces are able to yield global second-order convergence rates.

Congratulations, Amin!

Charles’ paper, A sharp interface method for an immersed viscoelastic solid, is now available on the arXiv. This paper develops an extension of the hyperelastic immersed boundary method that sharply resolves pressure discontinuities at fluid-structure interfaces by modifying the definition of the elastic stress tensor associated with the hyperelastic material response. Unlike most other sharp-interface immersed boundary methods, however, this approach allows us to use standard discretization methods that are “oblivious” to the presence of the pressure discontinuity. Numerical tests show the impact of the method on the accuracy of the overall scheme, and an approach is developed that allows us to compute the splitting efficiently.

Amin’s paper, An immersed interface method for faceted surfaces, is now available on the arXiv. This paper develops an extension of the immersed interface method (IIM) that is specialized to faceted surfaces (arising, for instance, from finite element structural models). It also establishes through extensive numerical examples that IIMs that use only the lowest-order jump conditions (for the pressure and viscous shear stress) at immersed interfaces are able to yield global second-order convergence rates.