Abstract
A numerical scheme to simulate three-dimensional two-way fluid–structure interaction (twFSI) problems of flows around a flexible fine structure is developed in this study. The partitioned approach is employed to separately calculate fluid flows and structure motions by the lattice Boltzmann method (LBM) and the geometrically exact Cosserat rod model (CRM), respectively. The fluid–structure interactions are calculated by the simple explicit coupling scheme combined with the contact detection algorithm and the fluid–structure interface reconstruction scheme. The contact detection algorithm utilizing the bounding volume hierarchy is adopted to reduce the computing time of data communication between the fluid and the structure solvers, while the fluid–structure interface reconstruction scheme utilizes the level set method to represent the moving fluid–structure interfaces. The proposed LBM–CRM–twFSI scheme is successfully validated in two experimental benchmarks of a single flexible structure deformation in a wind tunnel. The results confirm that the present scheme accurately calculates the equilibrium state and the time-dependent oscillatory motions of the structures exposed to airflows. The errors of the representative rod position between the experimental and numerical results for both benchmarks are within 5%. These validations confirm the practicability of the presently developed LBM–CRM–twFSI scheme for motions of flexible fine structures in fluid flows.
Highlights
Two-way fluid–structure interaction problems of the slender flexible structures are one of the essential research topics as they play important roles in biological flows and flows treated in ocean, civil, and textile engineering (Bourguet and Triantafyllou, 2016; Dey et al, 2018; Li et al, 2019; 2020; Mattis et al, 2015; Wu et al, 2014; and Zhu and Peskin, 2003)
As a fluid solver scitation.org/journal/adv of the Two-way fluid–structure interaction (twFSI) scheme, we focus on the lattice Boltzmann method (LBM), which is a computational fluid dynamics (CFD) technology based on the discretized Boltzmann equation
The LBM combined with the Galilean invariant momentum exchange method (GI-MEM) and the fluid–structure boundary reconstruction (fsBR) scheme is first verified in terms of the lattice resolution by calculating the flow past a rigid circular cylinder
Summary
Two-way fluid–structure interaction (twFSI) problems of the slender flexible structures are one of the essential research topics as they play important roles in biological flows and flows treated in ocean, civil, and textile engineering (Bourguet and Triantafyllou, 2016; Dey et al, 2018; Li et al, 2019; 2020; Mattis et al, 2015; Wu et al, 2014; and Zhu and Peskin, 2003). Compared with the conventional continuum-based CFD approaches, the LBM has the following advantages: simple fluid/structure representation of lattice nodes by binarized on/off treatments, easy implementation of no-slip boundary conditions of complex geometries, and easy parallelization using graphics processing units (GPUs) due to the discrete nature and locality of the computational algorithm (Agarwal et al, 2020; Lorenz et al, 2018; and Rinaldi et al, 2012) These features allow the LBM to be employed in simulations of the twFSI problems with complex geometry, flexible structures, or interacting boundaries. A boundary fitted moving mesh technique is not practical to solve the twFSI problems with complex boundaries or large deformations The latter approach utilizing a spatially uniform Eulerian grid to solve the fluid flow and a Lagrangian expression to solve the structure motions has been alternatively employed (Bavo et al, 2016).
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