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Earthquake damage estimation of the Koyna concrete gravity dam using explicit GFVM model considering fluid-structure interaction

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MATHEMATICS AND COMPUTERS IN SIMULATION 2022年第0期195卷 151-170页

作者： Sabbagh-Yazdi, Saeed-Reza Farhoud, Arwin Mohammadi, Amir Yazdinasabkarani, Elahe KN Toosi Univ Technol Civil Engn Dept 1346 Valiasr St Tehran 19697 Iran

In this paper, an Explicit Galerkin Finite Volume Method (E-GFVM) is employed to estimate damage paths in concrete structures through the definition of nonlinear behavior of concrete. Furthermore, to verify the accuracy and efficiency of the present method, the E-GFVM outcomes are compared with the Explicit Finite Element Method (E-FEM) which is a well-known numerical method for investigating numerous solid mechanics problems. Due to the essence of explicit methods, the method in question uses a few matrix operations in nonlinear analysis, so it diminishes computation workloads for time-dependent cases with small time-step. The reason for using E-GFVM was its simplicity and high accuracy in estimating stresses and displacements for the analysis of Computational Solid Mechanics (CSM) problems. Furthermore, one important feature of FVM is its local conservation properties which guarantee the global conservation of variables that provides more stability, particularly in dealing with complex problems. To model the nonlinear behavior of concrete, the two equivalent uniaxial stress-strain relations, taking into consideration the softening and hardening behavior in both compression and tension, are implemented in the proposed numerical method. In other words, the bi-axial concrete behavior is defined by applying the idea of current strength in principal stress space. Therefore, this study aims to introduce a new numerical method that in addition to reducing time consumption, can maintain the accuracy of the results. For reaching this purpose, first, the nonlinear behavior of concrete is modeled and two different specimens are placed under pure pressure and tension loads. The results calculated by the E-GFVM are compared with other literature. After verification of the nonlinear behavior of concrete using E-GFVM, the ability of the proposed method for analysis of a real-world case under time-dependent conditions, namely Koyna concrete gravity dam which experienced a destruc

关键词： Explicit GFVM Damaged concrete behavior Explicit FEM Koyna concrete gravity dam fluid-structure interaction

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Nonlinear flow control mechanism of two flexible flaps with fluid-structure interaction

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Acta Mechanica Sinica 2025年第2期41卷 116-131页

作者： Jiakun Han Chao Dong Jian Zhang Gang Chen College of Science Xi’an University of Science and TechnologyXi’an 710054China Beijing Institute of Space Long March Vehicle Beijing 100076China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China State Key Laboratory of Strength and Vibration for Mechanic Structures Shaanxi Key Laboratory of Service Environment and Control for Flight VehiclesSchool of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China

The flow control at low Reynolds numbers is one of the most promising technologies in the field of aerodynamics,and it is also an important source of the innovation for novel *** this study,a new way of nonlinear flow control by interaction between two flexible flaps is proposed,and their flow control mechanism is studied employing the self-constructed immersed boundary-lattice Boltzmann-finite element method(IB-LB-FEM).The effects of the difference in material properties and flap length between the two flexible flaps on the nonlinear flow control of the airfoil are *** is suggested that the relationship between the deformation of the two flexible flaps and the evolution of the vortex under the fluid-structure interaction(FSI).It is shown that the upstream flexible flap plays a key role in the flow control of the two flexible *** FSI effect of the upstream flexible flap will change the unsteady flow behind it and affect the deformation of the downstream flexible *** flexible flaps with different material properties and different lengths will change their own FSI characteristics by the induced vortex,effectively suppressing the flow separation on the airfoil’s upper *** interaction of two flexible flaps plays an extremely important role in improving the autonomy and adjustability of flow *** numerical results will provide a theoretical basis and technical guidance for the development and application of a new flap passive control technology.

关键词： Nonlinear flow control Flexible flap fluid-structure interaction Flow separation IB-LB-FEM

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A comprehensive assessment of accuracy of adaptive integration of cut cells for laminar fluid-structure interaction problems

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2022年 122卷 1-18页

作者： Kadapa, Chennakesava Wang, Xinyu Mei, Yue Univ Bolton Sch Engn Bolton BL3 5AB England Dalian Univ Technol Dept Engn Mech Dalian Peoples R China

Finite element methods based on cut-cells are becoming increasingly popular because of their advantages over formulations based on body-fitted meshes for problems with moving interfaces. In such methods, the cells (or elements) which are cut by the interface between two different domains need to be integrated using special techniques in order to obtain optimal convergence rates and accurate fluxes across the interface. The adaptive integration technique in which the cells are recursively subdivided is one of the popular techniques for the numerical integration of cut-cells due to its advantages over tessellation, particularly for problems involving complex geometries in three dimensions. Although adaptive integration does not impose any limitations on the representation of the geometry of immersed solids as it requires only point location algorithms, it becomes computationally expensive for recovering optimal convergence rates. This paper presents a comprehensive assessment of the adaptive integration of cut-cells for applications in computational fluid dynamics and fluid -structure interaction. We assess the effect of the accuracy of integration of cut cells on convergence rates in velocity and pressure fields, and then on forces and displacements for fluid-structure interaction problems by studying several examples in two and three dimensions. By taking the computational cost and the accuracy of forces and displacements into account, we demonstrate that numerical results of acceptable accuracy for FSI problems involving laminar flows can be obtained with only fewer levels of refinement. In particular, we show that three levels of adaptive refinement are sufficient for obtaining force and displacement values of acceptable accuracy for laminar fluid-structure interaction problems.

关键词： Incompressible Navier-Stokes Immersed boundary methods fluid-structure interaction CutFEM Adaptive integration Flow-induced vibrations

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A high-order partitioned fluid-structure interaction framework for vortex-induced vibration simulation

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APPLIED MATHEMATICAL MODELLING 2022年 105卷 321-339页

作者： Yu, Meilin Liu, Kan Zhu, Weidong Univ Maryland Baltimore Cty UMBC Dept Mech Engn Baltimore MD 21250 USA Shijiazhuang Tiedao Univ Sch Civil Engn Shaoxing Peoples R China

Vortex-induced vibration (VIV) is a highly nonlinear fluid-structure interaction (FSI) phenomenon, and its accurate prediction remains challenging. In this study, we developed a high-order partitioned FSI framework towards accurate simulation of the VIV phenomenon. The focus is on simulating the two-way coupled interaction between a flexibly mounted rigid body and its surrounding fluids. In the FSI framework, a high-order computational fluid dynamics method, i.e., flux reconstruction/correction procedure via reconstruction, is utilized to simulate the unsteady compressible Navier-Stokes equations in the arbitrary Lagrangian Eulerian format on unstructured moving grids. A linearized fluid-solid Riemann solver is employed to weakly couple fluid dynamics and rigid-body dynamics on the fluidsolid interface, which can effectively mitigate the so-called added-mass instability. Time marching is conducted through either the linearly implicit Rosenbrock-Wanner method or the explicit strong stability preserving Runge-Kutta method. The high-order FSI framework is verified with a challenging VIV phenomenon, i.e., VIV of a zero-mass cylinder in viscous flows, and has been used to study two VIV-related problems, namely, the nonlinear energy sink and oscillating foil based energy harvesting mechanism. (c) 2022 Elsevier Inc. All rights reserved.

关键词： fluid-structure interaction Vortex-induced vibration fluid-solid Riemann solver High-order methods Nonlinear energy sink Renewable energy harvesting

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A fluid-structure interaction analysis of design factor of subsurface irrigation PC dripper

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JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2022年第7期36卷 3469-3475页

作者： Kang, Woong Bhin Kim, Jeongsik Mo, Hyeonguk Eum, Dukho Lee, Sanghun Kim, Jinhyun Kim, Seolha Kyungpook Natl Univ Dept Precis Mech Engn Sangju 37224 South Korea Kyungpook Natl Univ Young Engn Educ Program Multidisciplinary Smart D Sangju 37224 South Korea Namkyung Co Ltd Hwaseong 18626 South Korea Rural Dev Adm Natl Inst Crop Sci Dept Southern Area Crop Sci Miryang 50424 South Korea

A subsurface drip irrigation system delivers water and nutrients directly to the plant root zone;other conventional nozzles-type or sprinklers-type irrigation are not used, and water-saving can reach 42-78%. In order to achieve this impact effectively, the drip irrigation requires a constant water supply under variations in pressure, which is so-called pressure compensating (PC) performance. The pressure compensating feature can be obtained by physical interaction between water flow and deformable silicone rubber in the PC dripper. In addition, pressure condition to ensure uniform water flow as a tresholding point also should be well designed, but it is generally have relied on the empiricial optimization. Here, we applied computational fluid dynamics to investigate water flow features in terms of flow rate and pressure drop of a conventional PC dripper. To understand the quantitative effects of changes in design parameters, we explored the fluid-structure interaction scheme in the CFD analysis between water flow and silicone rubber deformation. In this study, it is found that the marginal space for the silicone rubber deformation determined the threshold pressure condition;the friction condition of the tortuous channel of the dripper controlled the flow rate. This parametric study gave the logical insight to design new drip emitter with well-controlled and improved performance.

关键词： Computational fluid dynamics Dripper design factors fluid-structure interaction Pressure compensation Surface irrigation

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Coupling of the meshless finite volume particle method and the finite element method for fluid-structure interaction with thin elastic structures

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EUROPEAN JOURNAL OF MECHANICS B-fluidS 2022年 92卷 117-131页

作者： McLoone, Maryrose Quinlan, Nathan J. Natl Univ Ireland Galway Sch Engn Mech Engn Galway Ireland

A novel fluid-structure interaction (FSI) scheme is developed in this article, with the meshless finite volume particle method (FVPM) for fluid dynamics and the finite element (FE) solver FEBio for solid mechanics. Like smoothed particle hydrodynamics (SPH), FVPM is based on compactly supported particle kernels, but kernels are interpreted as a partitioning of volume, leading to a scheme with properties of both SPH and classical finite volume methods. Particle methods are advantageous for fluid modelling in FSI of highly deformable structures, as the particles can conform to the dynamic geometry of the fluid-structure interface. In FVPM, in particular, particles are rigorously truncated by boundaries, and the novel FSI scheme incorporates a sharp interface between the fluid and solid. A new method is described which avoids the possibility of unphysical communication between fluid particles separated by a thin structure. The method proposed here ensures that particles interact with the correct neighbour particles and boundaries, regardless of the particle overlap with the thin structure, allowing for particle size that can be chosen independently of structure thickness. The new method is validated for a hydrostatic water column on an elastic plate, a dam-break with elastic gate, a dam-break with a downstream elastic wall, and a 2-D model of a heart valve leaflet. In the latter two cases, the structure thickness is less than the particle diameter by a factor of up to 16. The results agree well with experimental data from the literature for fluid velocity field and solid deformation. Where quantitative data is available, the numerical results converge with decreasing particle size.(c) 2021 Elsevier Masson SAS. All rights reserved.

关键词： Finite volume particle method Particle method Meshless method fluid-structure interaction Thin structure Finite element method

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A FULL THREE-DIMENSIONAL TRANSIENT fluid-structure interaction MODEL FOR THE DYNAMIC CHARACTERISTICS PREDICTIONS OF BUMP-TYPE GAS FOIL JOURNAL BEARINGS

A FULL THREE-DIMENSIONAL TRANSIENT FLUID-STRUCTURE INTERACTI...

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ASME Turbomachinery Technical Conference and Exposition (Turbo Expo) on Collaborate, Innovate and Empower - Propulsion and Power for a Sustainable Future

作者： Li, Zhuocong Li, Zhigang Li, Jun Xi An Jiao Tong Univ Inst Turbomachinery Xian 710049 Peoples R China

ISBN: (纸本)9780791887059

Oil-lubricated bearings are used in most present-day rotating machinery due to their high load capacity. This bearing, however, requires a complicated lubrication system which significantly increases the operating cost of the equipment. Moreover, the problem of the heat generation of lubricated oil after a long time of operation cannot be ignored, especially in high-speed turbomachinery. As for oil-free turbomachinery, the gas-lubricated bearing is regarded as a revolutionary technology to support the rotor. Bump-type gas foil bearing (bump-type GFB) is one of the most widely used gas-lubricated bearings, due to its high speed, low wear, no pollution, high temperature and pressure resistance and other excellent properties. As one of the critical components in the rotor system of a rotating machinery, bump-type GFBs can provide not only the static load capacity but also the dynamic gas film response forces, significantly affecting the dynamic stability performance of the rotor system. Therefore, an accurate and efficient dynamic characteristics prediction method for bump-type GFBs is crucial for the industrial safe operation of the rotating machinery system. This paper focuses on the assessment and validation of a novel numerical method for the dynamic coefficients prediction of bump-type gas foil journal bearings (bump-type GFJBs). To predict the dynamic characteristics of bump-type GFJBs, in this paper, a novel full three-dimensional (3D) transient fluidstructure coupled numerical method was proposed, based on the finite element analysis (FEA) and the computational fluid dynamics (CFD). In order to improve computational efficiency and conform more to the bearing actual situations, a multiple-frequency elliptical-orbit rotor whirling model for arbitrary eccentric positions was proposed to define the rotor whirling motion, based on the mesh deformation techniques. The present full 3D transient CFD/FEA method was validated by the published experimental data of the dyn

关键词： bump-type gas foil journal bearings fluid-structure interaction multiple-frequency elliptical-orbit rotor whirling model eccentricity ratio dynamic characteristics

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Stroke risk evaluation for patients with atrial fibrillation: Insights from left atrial appendage with fluid-structure interaction analysis

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COMPUTERS IN BIOLOGY AND MEDICINE 2022年 148卷 105897-105897页

作者： Fang, Runxin Wang, Zidun Zhao, Xie Wang, Jun Li, Yang Zhang, Yanjuan Chen, Qiang Wang, Jiaqiu Liu, Quanjun Chen, Minglong Li, Zhiyong Southeast Univ Sch Biol Sci & Med Engn Nanjing 210096 Peoples R China Nanjing Med Univ Affiliated Hosp 1 Nanjing 210029 Peoples R China Nanjing Univ Med Sch Affiliated Hosp Nanjing Drum Tower Hosp Nanjing 210008 Peoples R China Southeast Univ Zhongda Hosp Affiliated Hosp Nanjing 210009 Peoples R China Queensland Univ Technol QUT Sch Mech Med & Proc Engn Brisbane Qld 4001 Australia

The majority of cardioembolic strokes in patients with non-valvular atrial fibrillation (NVAF) are resulted from clot formation in the left atrial appendage (LAA). Current stroke risk stratification is based on the overall risks estimated from demographic and clinical profiles but not on individual anatomy or physiology. We aim to explore the differences in LAA morphological and hemodynamic parameters by comparing patients with and without a stroke history. Thirty-nine patients with persistent NVAF were included. Of these, 17 patients without a stroke history (non-stroke group) were compared with 22 patients with a history of stroke (stroke group). Their LAA geometric models were first reconstructed, and the morphological parameters were then measured. Furthermore, their LAA hemodynamic parameters were calculated by fluid-structure interaction analysis. Moreover, particle residual rates (PRR) and blood renewal rates (BRR) analyses were also employed to characterize the thrombogenesis dynamics. The results showed that compared to the non-stroke group, the stroke group had significant smaller LAA tortuosity and LAA orifice area, and significantly lower LAA orifice velocities (0.16 +/- 0.10 vs 0.15 +/- 0.06 cm/s;p = 0.044), but higher PRR (14.58 +/- 9.43 vs 9.25 +/- 4.67;p = 0.040) and BRR (52.41 +/- 18.11 vs 38.36 +/- 24.07;p = 0.044). These LAA morphological and hemodynamic parameters may be used to assess stroke risk in patients with NVAF.

关键词： Atrial fibrillation Stroke risk Left atrial appendage Morphology Hemodynamics fluid-structure interaction

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Comparative study of arterial wall models for numerical fluid-structure interaction simulation of aortic arch aneurysms

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JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2022年第5期44卷 1-14页

作者： Ferreira da Silva, Mario Luis Goncalves, Saulo de Freitas Huebner, Rudolf Univ Fed Minas Gerais Dept Mech Engn Grad Program Mech Engn Antonio Carlos AvePampulha6627 BR-31270901 Belo Horizonte MG Brazil Univ Fed Minas Gerais Dept Mech Engn Antonio Carlos AvePampulha 6627 BR-31270901 Belo Horizonte MG Brazil

The arterial wall model adopted in the fluid-structural numerical simulations is directly related to its mechanical response, as well as to the flow field. The work developed here compares different arterial wall models for an aneurysm located in the aortic arch. Isotropic linear elastic, Yeoh isotropic polynomial hyperelastic, and Holzapfel anisotropic hyperelastic models were used. Physiological boundary conditions were used throughout the cardiac cycle, and the non-Newtonian model of Carreau was used as rheological model. The fluid domain was discretized by the finite volume method, and the solid domain was discretized by the finite element method. The results showed that the less stiff model, i.e., the isotropic linear elastic model with modulus of elasticity E = 1 MPa, had a greater increase in the aneurysmal sac, which favored recirculation and induced low values of wall shear stress, which may be an indication of intraluminal thrombus formation overestimation. However, the peak of maximum principal stress, which occurred at the junction of supra-aortic branches with aortic arch, was higher in the Yeoh model, which may represent an overestimation of the rupture risk in stiffer models.

关键词： Aortic wall model fluid-structure interaction Aortic arch aneurysm Pulsatile blood flow Hemodynamics

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Spline-based space-time finite element approach for fluid-structure interaction with a focus on enclosed domains

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2022年第0期114卷 210-224页

作者： Make, Michel Spenke, Thomas Hosters, Norbert Behr, Marek Rhein Westfal TH Aachen JARA Ctr Simulat & Data Sci JARA CSD Chair Computat Anal Tech Syst Cats Schinkelstr 2 D-52062 Aachen Germany

Non-Uniform Rational B-Spline (NURBS) surfaces are commonly used within Computer-Aided Design (CAD) tools to represent geometric objects. When using isogeometric analysis (IGA), it is possible to use such NURBS geometries for numerical analysis directly. Analyzing fluid flows, however, requires complex three-dimensional geometries to represent flow domains. Defining a parametrization of such volumetric domains using NURBS can be challenging and is still an ongoing topic in the IGA community. With the recently developed NURBS-enhanced finite element method (NEFEM), the favorable geometric characteristics of NURBS are used within a standard finite element method. This is achieved by enhancing the elements touching the boundary by using the NURBS geometry itself. In the current work, a new variation of NEFEM is introduced, which is suitable for three-dimensional space-time finite element formulations. The proposed method makes use of a new mapping which results in a non-Cartesian formulation suitable for fluid structure interaction (FSI). This is demonstrated by combining the method with an IGA formulation in a strongly-coupled partitioned framework for solving FSI problems. The framework yields a fully spline-based representation of the fluid structure interface through a single NURBS. The coupling conditions at the fluid-structure interface are enforced through a Robin-Neumann type coupling scheme. This scheme is particularly useful when considering incompressible fluids in fully Dirichlet-bounded and curved problems, as it satisfies the incompressibility constraint on the fluid for each step within the coupling procedure. The accuracy and performance of the introduced spline-based space-time finite element approach and its use within the proposed coupled FSI framework are demonstrated using a series of two-and three-dimensional benchmark problems.

关键词： Non-Cartesian NURBS-enhanced finite elements Spline-based methods fluid-structure interaction Exact geometry representation Fully Dirichlet-bounded problems Fully enclosed domains

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