An immersed-boundary/isogeometric method for fluid–structure interaction involving thin shells

Nitti, Alessandro; Kiendl, Josef; Reali, Alessandro; Tullio, Marco D. de

doi:10.1016/j.cma.2020.112977

Cited by 36 publications

(17 citation statements)

References 91 publications

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“…The numerical scheme and the IB procedure are thoroughly described and explored in the context of a fluid–structure-interaction solver in Nitti et al. (2020) and de Tullio & Pascazio (2016). In the present simulations the local relative spacing among Lagrangian markers is set to , following the numerical experiments presented in Nitti et al.…”

Section: Methodsmentioning

confidence: 99%

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Numerical investigation of turbulent features past different mechanical aortic valves

2022

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Flow through mechanical aortic valves (MAVs) has been constantly associated to higher haemolysis and platelet activation levels with respect to native valves, due to non-physiologic haemodynamic features. Both computational and experimental investigations have correlated the blood damage to augmented levels of turbulent stress downstream of MAVs. This study provides a computational estimation, drawn from high-resolution direct numerical simulations, of turbulent and fluctuating viscous stresses in three different MAV configurations, at subsequent stages of the cardiac cycle. The configurations comprise a St. Judes Medical Regent valve (SJMV), a Lapeyre-Triflo FURTIVA valve (LTFV) with three leaflets, and a SJMV with vortex generators (VGs). Non-standard configurations are expected to mitigate the mean stress level on blood constituents reducing the turbulent production. Computations are carried out by means of a finite-difference flow solver with a direct-forcing immersed boundary technique to handle fixed and moving bodies. The VGs are found to provide instabilities which corrupt the Kármán-like vortex shedding downstream of the leaflets, reducing the intensity of turbulent kinetic energy at the peak flow rate, thus lowering the local Reynolds shear stress. Conversely, the LTFV configuration provides comparable haemodynamic performance at peak flow rate but further reduced stress level in the deceleration phase. These interpretations are supported by probability density distributions from three-dimensional fields, and further corroborated by a pointwise mapping of the Taylor length scale and local energy spectra. The outcomes of this study might potentially be exploited to improve the design of new-generation MAVs, with the aim of decreasing the risk of thromboembolic complications.

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Section: Methodsmentioning

confidence: 99%

“…In the present simulations the local relative spacing among Lagrangian markers is set to , following the numerical experiments presented in Nitti et al. (2020). According to the geometric arrangement illustrated in figure 1( c ), the fluid domain which contains the aortic root has inflow–outflow conditions in the streamwise direction.…”

Section: Methodsmentioning

confidence: 99%

Numerical investigation of turbulent features past different mechanical aortic valves

2022

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“…Thus, isogeometric KL shells [39][40][41][42][43][44][45][46][47] have gained popularity in the simulation and analysis community due to their computationally efficient rotation-free formulation and model simplification into the midsurface representation. The formulations have been previously demonstrated as an effective solution for the analysis of complex problems [48][49][50][51][52][53][54][55][56][57][58][59][60][61], including wind turbine blades [62][63][64][65][66][67][68][69][70][71][72] and heart valves [73][74][75][76][77][78][79][80][81]. While computational efficiency is an important factor in numerical analysis, KL shells have limited accuracy in predicting the transverse stress and strain states.…”

Section: Introductionmentioning

confidence: 99%

Blended isogeometric Kirchhoff–Love and continuum shells

Liu

Johnson

Rajanna

et al. 2021

Computer Methods in Applied Mechanics and Engineering

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The computational modeling of thin-walled structures based on isogeometric analysis (IGA), non-uniform rational B-splines (NURBS), and Kirchhoff-Love (KL) shell formulations has attracted significant research attention in recent years. While these methods offer numerous benefits over the traditional finite element approach, including exact representation of the geometry, naturally satisfied high-order continuity within each NURBS patch, and computationally efficient rotation-free formulations, they also present a number of challenges in modeling real-world engineering structures of considerable complexity. Specifically, these NURBS-based engineering models are usually comprised of numerous patches, with discontinuous derivatives, nonconforming discretizations, and non-watertight connections at their interfaces. Moreover, the analysis of such structures often requires the full stress and strain tensors (i.e., including the transverse normal and shear components) for subsequent failure analysis and remaining life prediction. Despite the efficiency provided by the KL shell, the formulation cannot accurately predict the response in the transverse directions due to its kinematic assumptions. In this work, a penalty-based formulation for the blended coupling of KL and continuum shells is presented. The proposed approach embraces both the computational efficiency of KL shells and the availability of the full-scale stress/strain tensors of continuum shells where needed by modeling critical structural components using continuum shells and other components using KL shells. The proposed method enforces the displacement and rotational continuities in a variational manner and is applicable to non-conforming and non-smooth interfaces. The efficacy of the developed method is demonstrated through a number of benchmark studies with a variety of analysis configurations, including linear and nonlinear analyses, matching and non-matching discretizations, and isotropic and composite materials. Finally, an aircraft horizontal stabilizer is considered to demonstrate the applicability of the proposed blended shells to real-world engineering structures of significant complexity. c

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“…13 Specifically, incompressible unsteady Stokes flows are considered, together with the no-slip interface condition enforced on the immersed structure. But it is also important to point out that there have been many extensions of the original IBM framework with different treatments for the Lagrangian equations of motion or the fluid dynamics, [30][31][32] and reducedorder modeling can be considered in those settings as well. Our starting point is a semi-discrete representation of the IBM model, so that the dynamics of fluid and structure motion can be expressed as coupled ODEs, which can then be placed in the reduced-order modeling framework.…”

Section: Introductionmentioning

confidence: 99%

Projection‐based model reduction for the immersed boundary method

Luo

Hao

2021

Numer Methods Biomed Eng

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Fluid-structure interactions are central to many biomolecular processes, and they impose a great challenge for computational and modeling methods. In this paper, we consider the immersed boundary method (IBM) for biofluid systems, and to alleviate the computational cost, we apply reduced-order techniques to eliminate the degrees of freedom associated with the large number of fluid variables. We show how reduced models can be derived using Petrov-Galerkin projection and subspaces that maintain the incompressibility condition. More importantly, the reduced-order model (ROM) is shown to preserve the Lyapunov stability. We also address the practical issue of computing coefficient matrices in the ROM using an interpolation technique. The efficiency and robustness of the proposed formulation are examined with test examples from various applications.

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An immersed-boundary/isogeometric method for fluid–structure interaction involving thin shells

Cited by 36 publications

References 91 publications

Numerical investigation of turbulent features past different mechanical aortic valves

Numerical investigation of turbulent features past different mechanical aortic valves

Blended isogeometric Kirchhoff–Love and continuum shells

Projection‐based model reduction for the immersed boundary method

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