A robust computational framework for simulating the dynamics of large assemblies of highly-flexible fibers immersed in viscous flow

A robust computational framework for simulating the dynamics of large assemblies of highly-flexible fibers immersed in viscous flow

Koshakji, Anwar (Massachusetts Institute of Technology)
Chomette, Grégoire (Massachusetts Institute of Technology)
Turner, Jeffrey (US Army DEVCOM Armaments Center)
Jablonski, Jonathan (US Army DEVCOM Armaments Center)
Haynes, Aisha (US Army DEVCOM Armaments Center)
Carlucci, Donald (US Army DEVCOM Armaments Center)
Giovanardi, Bianca (TU Delft Aerospace Structures & Computational Mechanics; Massachusetts Institute of Technology)
Radovitzky, Raúl A. (Massachusetts Institute of Technology)

2023

The dynamic response of flexible filaments immersed in viscous fluids is important in cell mechanics, as well as other biological and industrial processes. In this paper, we propose a parallel computational framework to simulate the fluid-structure interactions in large assemblies of highly-flexible filaments immersed in a viscous fluid. We model the deformation of each filament in 3D with a C¹ geometrically-exact large-deformation finite-element beam formulation and we describe the hydrodynamic interactions by a boundary element discretization of the Stokeslet model. We incorporate a contact algorithm that prevents fiber interpenetration and avoids previously reported numerical instabilities in the flow, thus providing the ability to describe the complex evolution of large clouds of fibers over long time spans. In order to support the required long-term integration, we use implicit integration of the solid-fluid-contact coupling. We address the challenges associated with the solution of the large and dense linear system for the hydrodynamic interactions by taking advantage of the massive parallelization offered by Graphic Processing Units (GPUs), which we test up to 1000 fibers and 45000 degrees of freedom. We validate the framework against the well-established response of the sedimentation of a single fiber under gravity in the low to moderate flexibility range. We then reproduce previous results and provide additional insights in the large to extreme flexibility range. Finally, we apply the framework to the analysis of the sedimentation of large clouds of filaments under gravity, as a function of fiber flexibility. Owing to the long time spans afforded by our computational framework, our simulations reproduce the breakup response observed experimentally in the lower flexibility range and provide new insights into the breakup of the initial clouds in the higher flexibility range.

Beam contact
Boundary element method
Flexible filaments in Stokes flow
Fluid-structure interaction
Graphic processing units (GPU)
Large-deformation beam elements

http://resolver.tudelft.nl/uuid:c1f58038-1caf-406f-b953-8b829e7a920f

https://doi.org/10.1016/j.jcp.2022.111774

2023-05-29

0021-9991

Journal of Computational Physics, 474

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Anwar Koshakji, Grégoire Chomette, Jeffrey Turner, Jonathan Jablonski, Aisha Haynes, Donald Carlucci, Bianca Giovanardi, Raúl A. Radovitzky