scholarly journals A Monolithic Approach of Fluid–Structure Interaction by Discrete Mechanics

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 95
Author(s):  
Stéphane Vincent ◽  
Jean-Paul Caltagirone

The unification of the laws of fluid and solid mechanics is achieved on the basis of the concepts of discrete mechanics and the principles of equivalence and relativity, but also the Helmholtz–Hodge decomposition where a vector is written as the sum of divergence-free and curl-free components. The derived equation of motion translates the conservation of acceleration over a segment, that of the intrinsic acceleration of the material medium and the sum of the accelerations applied to it. The scalar and vector potentials of the acceleration, which are the compression and shear energies, give the discrete equation of motion the role of conservation law for total mechanical energy. Velocity and displacement are obtained using an incremental time process from acceleration. After a description of the main stages of the derivation of the equation of motion, unique for the fluid and the solid, the cases of couplings in simple shear and uniaxial compression of two media, fluid and solid, make it possible to show the role of discrete operators and to find the theoretical results. The application of the formulation is then extended to a classical validation case in fluid–structure interaction.

2009 ◽  
Vol 46 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Ryo Torii ◽  
Marie Oshima ◽  
Toshio Kobayashi ◽  
Kiyoshi Takagi ◽  
Tayfun E. Tezduyar

2019 ◽  
Vol 92 (2) ◽  
pp. 129-147 ◽  
Author(s):  
Andrea La Spina ◽  
Christiane Förster ◽  
Martin Kronbichler ◽  
Wolfgang A. Wall

2012 ◽  
Author(s):  
Sang Hyuk Lee ◽  
Seongwon Kang ◽  
Nahmkeon Hur

In the present study, a problem of the hemodynamic fluid-structure interaction (FSI) in the carotid artery was analyzed using a numerical approach. To predict the blood flow and arterial deformation, a framework for the FSI analysis was developed by coupling computational fluid dynamics (CFD) and solid mechanics (CSM) approaches. Using this framework, the hemodynamics of the carotid artery was simulated with the patient-specific clinical data of the arterial geometry, pulsatile blood flow and blood rheology. It is found that the hemodynamic characteristics of the carotid artery are significantly affected by its geometric factors and flow conditions, and relatively low values of the wall shear stress were observed in the post-plaque dilated region of the carotid bifurcated area. Since these characteristics of the carotid artery are affected by the cerebral circulation system, the effects of the cardiac output and the distal vascular resistance on hemodynamics were also analyzed.


2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Zheng Li ◽  
Ye Chen ◽  
Siyuan Chang ◽  
Haoxiang Luo

Abstract We present a novel reduced-order glottal airflow model that can be coupled with the three-dimensional (3D) solid mechanics model of the vocal fold tissue to simulate the fluid–structure interaction (FSI) during voice production. This type of hybrid FSI models have potential applications in the estimation of the tissue properties that are unknown due to patient variations and/or neuromuscular activities. In this work, the flow is simplified to a one-dimensional (1D) momentum equation-based model incorporating the entrance effect and energy loss in the glottis. The performance of the flow model is assessed using a simplified yet 3D vocal fold configuration. We use the immersed-boundary method-based 3D FSI simulation as a benchmark to evaluate the momentum-based model as well as the Bernoulli-based 1D flow models. The results show that the new model has significantly better performance than the Bernoulli models in terms of prediction about the vocal fold vibration frequency, amplitude, and phase delay. Furthermore, the comparison results are consistent for different medial thicknesses of the vocal fold, subglottal pressures, and tissue material behaviors, indicating that the new model has better robustness than previous reduced-order models.


Author(s):  
Bhuiyan Shameem Mahmood Ebna Hai ◽  
Markus Bause

Will an aircraft wing have the structural integrity to withstand the forces or fail when it’s racing at a full speed? Fluid-structure interaction (FSI) analysis can help you to answer this question without the need to create costly prototypes. However, combining fluid dynamics with structural analysis traditionally poses a formidable challenge for even the most advanced numerical techniques due to the disconnected, domain-specific nature of analysis tools. In this paper, we present the state-of-the-art in computational FSI methods and techniques that go beyond the fundamentals of computational fluid and solid mechanics. In fact, the fundamental rule require transferring results from the computational fluid dynamics (CFD) analysis as input into the structural analysis and thus can be time-consuming, tedious and error-prone. This work consists of the investigation of different time stepping scheme formulations for a nonlinear fluid-structure interaction problem coupling the incompressible Navier-Stokes equations with a hyperelastic solid based on the well established Arbitrary Lagrangian Eulerian (ALE) framework. Temporal discretization is based on finite differences and a formulation as one step-θ scheme, from which we can extract the implicit euler, crank-nicolson, shifted crank-nicolson and the fractional-step-θ schemes. The ALE approach provides a simple, but powerful procedure to couple fluid flows with solid deformations by a monolithic solution algorithm. In such a setting, the fluid equations are transformed to a fixed reference configuration via the ALE mapping. The goal of this work is the development of concepts for the efficient numerical solution of FSI problem and the analysis of various fluid-mesh motion techniques, a comparison of different second-order time-stepping schemes. The time discretization is based on finite difference schemes whereas the spatial discretization is done with a Galerkin finite element scheme. The nonlinear problem is solved with Newton’s method. To control computational costs, we apply a simplified version of a posteriori error estimation using the dual weighted residual (DWR) method. This method is used for the mesh adaption during the computation. The implementation using the software library package DOpElib and deal.II serves for the computation of different fluid-structure configurations.


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