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A viscoelastic fluid-structure interaction model for carotid arteries under pulsatile flow

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2015年第5期31卷 n/a-N.PAG页

作者： Wang, Zhongjie Wood, Nigel B. Xu, Xiao Yun Univ London Imperial Coll Sci Technol & Med Dept Chem Engn London SW7 2AZ England

In this study, a fluid-structure interaction model (FSI) incorporating viscoelastic wall behaviour is developed and applied to an idealized model of the carotid artery under pulsatile flow. The shear and bulk moduli of the arterial wall are described by Prony series, where the parameters can be derived from in vivo measurements. The aim is to develop a fully coupled FSI model that can be applied to realistic arterial geometries with normal or pathological viscoelastic wall behaviour. Comparisons between the numerical and analytical solutions for wall displacements demonstrate that the coupled model is capable of predicting the viscoelastic behaviour of carotid arteries. Comparisons are also made between the solid only and FSI viscoelastic models, and the results suggest that the difference in radial displacement between the two models is negligible. Copyright (c) 2015 John Wiley & Sons, Ltd.

关键词： carotid artery viscoelastic model pulsatile flow fluid-structure interaction

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Dynamic and static study of the fluid-structure interaction problem on elastic box plate

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JOURNAL OF VIBROENGINEERING 2015年第2期17卷 957-966页

作者： Hao, Ya-juan Gong, Ming-ming Yang, Ai-min Yanshan Univ Coll Sci Qinhuangdao 066004 Peoples R China Hebei United Univ Coll Sci Tangshan 063009 Peoples R China

The influence of coupling to the fluid field is neglected in the classic fluid mechanics theory. United Lagrangian-Eulerian method is used to solve the fluid-structure interaction (FSI) problem of the nonviscous and incompressible fluid flow around an elastic box plate taking into account the influence of deformation of the elastic plate. In this approach, each material is described in its preferred reference frame. fluid flows are given in Eulerian coordinates whereas the elastic body is treated in a Lagrangian framework. The coupling between the fluid and elastic body domains is kinematic and dynamic conditions at the body surface. The kinematic and dynamic conditions are given in Eulerian and Lagrangian coordinates. The dynamic equation of the elastic box plate is expressed combining the dynamic conditions at the interface. The knowledge of both dynamic and static deformations, static pressure and velocity distributions is given by using the Taylor expansions method. The effect of plate deformation is taken into account for the obtained solutions.

关键词： fluid-structure interaction united Lagrangian-Eulerian method elastic box plate dynamic equation deformation

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On a Partitioned Strong Coupling Algorithm for Modeling fluid-structure interaction

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INTERNATIONAL JOURNAL OF APPLIED MECHANICS 2015年第2期7卷

作者： He, Tao Shanghai Normal Univ Dept Civil Engn Shanghai 201418 Peoples R China Univ Birmingham Sch Civil Engn Birmingham B15 2TT W Midlands England

This paper presents a partitioned strong coupling algorithm for fluid-structure interaction in the arbitrary Lagrangian-Eulerian finite element framework. The incompressible Navier-Stokes equations are solved by the semi-implicit characteristic-based split (CBS) scheme while the structural equations are temporally advanced by the Bathe method. The celled-based smoothed finite element method is adopted for the solution of a geometrically nonlinear solid. To update the dynamic mesh, the moving submesh approach is performed in conjunction with the ortho-semi-torsional spring analogy method. A mass source term is implanted into the pressure Poisson equation to respect the geometric conservation law for the fractional-step-type CBS fluid solver. The iterative solution is achieved by fixed-point method with Aitken's.2 accelerator. The proposed methodology is validated against flow-induced oscillations of a bluff body and a flexible body. The overall numerical results agree well with the available data. Some important flow phenomena have been disclosed successfully.

关键词： fluid-structure interaction arbitrary Lagrangian-Eulerian finite element method partitioned strong coupling algorithm vortex-induced vibrations

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Stability of Carotid Artery Under Steady-State and Pulsatile Blood Flow: A fluid-structure interaction Study

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JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME 2015年第6期137卷 061007-061007页

作者： Khalafvand, Seyed Saeid Han, Hai-Chao Univ Texas San Antonio Dept Mech Engn San Antonio TX 78249 USA

It has been shown that arteries may buckle into tortuous shapes under lumen pressure, which in turn could alter blood flow. However, the mechanisms of artery instability under pulsatile flow have not been fully understood. The objective of this study was to simulate the buckling and post-buckling behaviors of the carotid artery under pulsatile flow using a fully coupled fluid-structure interaction (FSI) method. The artery wall was modeled as a nonlinear material with a two-fiber strain-energy function. FSI simulations were performed under steady-state flow and pulsatile flow conditions with a prescribed flow velocity profile at the inlet and different pressures at the outlet to determine the critical buckling pressure. Simulations were performed for normal (160 ml/min) and high (350 ml/min) flow rates and normal (1.5) and reduced (1.3) axial stretch ratios to determine the effects of flow rate and axial tension on stability. The results showed that an artery buckled when the lumen pressure exceeded a critical value. The critical mean buckling pressure at pulsatile flow was 17-23% smaller than at steady-state flow. For both steady-state and pulsatile flow, the high flow rate had very little effect (<5%) on the critical buckling pressure. The fluid and wall stresses were drastically altered at the location with maximum deflection. The maximum lumen shear stress occurred at the inner side of the bend and maximum tensile wall stresses occurred at the outer side. These findings improve our understanding of artery instability in vivo.

关键词： fluid-structure interaction artery buckling pulsatile flow critical pressure finite element analysis computational fluid dynamics

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FINITE ELEMENT MODELING OF THE HUMAN COCHLEA USING fluid-structure interaction METHOD

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JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 2015年第3期15卷 1550039-1550039页

作者： Xu, Lifu Huang, Xinsheng Ta, Na Rao, Zhushi Tian, Jiabin Shanghai Jiao Tong Univ State Key Lab Mech Syst & Vibrat Inst Vibrat Shock & Noise Shanghai 200240 Peoples R China Fudan Univ Zhongsan Hosp Dept Otorhinolaryngol Shanghai 200032 Peoples R China

In this paper, a 3D finite element (FE) model of human cochlea is developed. This passive model includes the structure of oval window, round window, basilar membrane (BM) and cochlear duct which is filled with fluid. Orthotropic material property of the BM is varying along its length. The fluid-structure interaction (FSI) method is used to compute the responses in the cochlea. In particular, the viscous fluid element is adopted for the first time in the cochlear FE model, so that the effects of shear viscosity in the fluid are considered. Results on the cochlear impedance, BM response and intracochlear pressure are obtained. The intracochlear pressure includes the scala vestibule and scala tympani pressure are extracted and used to calculate the transfer functions from equivalent ear canal pressures to scala pressures. The reasonable agreements between the model results and the experimental data in the literature prove the validity of the cochlear model for simulating sound transmission in the cochlea. Moreover, this model predicted the transfer function from equivalent ear canal pressures to scala pressures which is the input to the cochlear partition.

关键词： Finite element model human cochlea fluid-structure interaction basilar membrane intracochlear pressure

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MODELING OF ILIAC ARTERY ANEURYSM USING fluid-structure interaction

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JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY 2015年第1期15卷 1550041-1550041页

作者： Sabooni, Hatef Hassani, Kamran Bahraseman, Hamidreza Ghasemi Islamic Azad Univ Dept Biomech Sci & Res Branch Tehran Iran Tennessee Technol Univ Dept Mech Engn Cookeville TN 38505 USA

The aneurysm of iliac artery is a rare entity and there are few computational models that have studied the disease. In this study, we have presented the flow patterns in the aneurysmal artery using fluid-structure interaction method. The blood was assumed Newotonian, pulsatile, laminar, incompressible, and homogenous. The geometry of the model was made based on CT images of clinical cases. Using the computational method, we have obtained the velocity and pressure contours, shear rates and vortices for the healthy and aneurysmal artery. The results show that a pressure maximum was found at the midpoint of the dilation. The vortices are formed in the aneurysmal area(26) and shear rates do not change much. However, the rate increased in the neck of aneurysms. Furthermore, the aneurysm with bigger dilation tend to rupture due to more shear rates in the neck and the velocity at peak systole decreases in the aneurysmal area due to increase of the artery diameter. We have compared our results with some available relevant clinical data in discussion section.

关键词： Iliac aneurysm fluid-structure interaction computational

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Particle-image velocimetry investigation of the fluid-structure interaction mechanisms of a natural owl wing

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BIOINSPIRATION & BIOMIMETICS 2015年第5期10卷 056009-056009页

作者： Winzen, A. Roidl, B. Schroeder, W. Rhein Westfal TH Aachen Inst Aerodynam D-52062 Aachen Germany

The increasing interest in the development of small flying air vehicles has given rise to a strong need to thoroughly understand low-speed aerodynamics. The barn owl is a well-known example of a biological system that possesses a high level of adaptation to its habitat and as such can inspire future small-scale air vehicle design. The combination of the owl-specific wing geometry and plumage adaptations with the flexibility of the wing structure yields a highly complex flow field, still enabling the owl to perform stable and at the same time silent low-speed gliding flight. To investigate the effects leading to such a characteristic flight, time-resolved stereoscopic particle-image velocimetry (TR-SPIV) measurements are performed on a prepared natural owl wing in a range of angles of attack 0 degrees <= alpha <= 6 degrees and Reynolds numbers 40 000 <= Re-c <= 120 000 based on the chord length at a position located at 30% of the halfspan from the owl's body. The flow field does not show any flow separation on the suction side, whereas flow separation is found on the pressure side for all investigated cases. The flow field on the pressure side is characterized by large-scale vortices which interact with the flexible wing structure. The good agreement of the shedding frequency of the pressure side vortices with the frequency of the trailing-edge deflection indicates that the structural deformation is induced by the flow field on the pressure side. Additionally, the reduction of the time-averaged mean wing curvature at high Reynolds numbers indicates a passive lift-control mechanism that provides constant lift in the entire flight envelope of the owl.

关键词： natural owl wing time-resolved stereoscopic PIV fluid-structure interaction

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Performance of Buried Tunnels Subjected to Surface Blast Incorporating fluid-structure interaction

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JOURNAL OF PERFORMANCE OF CONSTRUCTED FACILITIES 2015年第3期29卷 04014084-04014084页

作者： Koneshwaran, Sivalingam Thambiratnam, David P. Gallage, Chaminda Queensland Univ Technol Fac Sci & Engn Brisbane Qld 4001 Australia

This paper uses finite-element techniques to investigate the performance of buried tunnels subjected to surface blasts incorporating fully coupled fluid-structure interaction and appropriate material models that simulate strain-rate effects. Modeling techniques are first validated against existing experimental results and then used to treat the blast-induced shock-wave propagation and tunnel response in dry and saturated sands. Results show that the tunnel buried in saturated sand responds earlier than that in dry sand. Tunnel deformations decrease with distance from the explosive in both sands, as expected. In the vicinity of the explosive, the tunnel buried in saturated sand suffered permanent deformation in both axial and circumferential directions, whereas the tunnel buried in dry sand recovered from most of the axial deformation. Overall, response of the tunnel in saturated sand is more severe for a given blast event and shows the detrimental effect of pore water on the blast response of buried tunnels. The validated modeling techniques developed in this paper can be used to investigate the blast response of tunnels buried in dry and saturated sands.

关键词： Explosion Tunnel fluid-structure interaction Material models Saturated sand Strain-rate effects Centrifuge test Finite-element modeling

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Numerical Research on Segmented Flexible Airfoils Considering fluid-structure interaction

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Procedia Engineering 2015年 99卷 57-66页

作者： Dong Hefeng Wang Chenxi Li Shaobin Song Xi Zhen National Key Laboratory on Aero-Engines School of Energy and Power Engineering Beihang University. Beijing 100191 China

This paper investigated four kinds of segmented flexible airfoils with membrane material on the upper surface and rigid structure on the lower surface. fluid-structure interaction method was adopted in the numerical simulation for the aerodynamic characteristics and response between flow field and structure of the segmented flexible airfoils. The research focuses on influence of flexible deformation on the lift and drag characteristics and the aerodynamic load distribution of four segmented flexible airfoils at Reynolds number of 1.35×10 5 . The results show that the segmented flexible airfoils perform a higher maximum lift coefficient, and effectively delay the stall. At the higher angles of attack, the deformation of the flexible thin membrane could reduce the scale of the separation vortexes. Meanwhile the tiny vortex generated between the flexible segments with the effect called “fluid Roller Bearing” would impel the separated boundary layer to reattach to the airfoil surface especially on the first half chord region. The three-segment flexible airfoil was proved to be the best airfoil among the four airfoils, which could increase the lift coefficient by 39% near the stall angle of attack compared with its rigid counterpart.

关键词： fluid-structure interaction distribution forms flexible airfoil aerodynamic characteristics

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Dynamical Stability Analysis of a fluid structure interaction System Using a High Fidelity Navier-stokes Solver

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Procedia Engineering 2016年 144卷 883-890页

作者： Chandan Bose Sandeep Badrinath Sayan Gupta Sunetra Sarkar Department of Applied Machanics Indian Institute of Technology Madras Chennai 600 036 India Department of Aerospace Engineering Indian Institute of Technology Madras Chennai 600 036 India

The present paper investigates the flow induced dynamics of a non-linear fluid-structure interaction (FSI) system comprising of a symmetrical NACA 0012 airfoil supported by non-linear springs. Two methods are used in calculating the aerodynamic loads: a linear analytical approach and a full Navier-Stokes (N-S) solution. The analytical approach is based on the assumption of potential flow theory and a rigid wake. Wind velocity as a bifurcation parameter shows that the structural response undergoes a supercritical Hopf bifurcation. However, the analytical loads predict unrealistic bifurcation onset at low values of solid to fluid added mass ratio ( μ ) relevant to the application of flapping wing micro air vehicles (MAVs), showing the extremely large amplitude of oscillations. These observations render the use of an inviscid approach meaningless at such parametric regimes. Hence, we propose to use a N-S solver to emphasize the limit of applicability of the linear aerodynamic theory. Moreover, the inclusion of the viscous effects can potentially result in interesting dynamical behavior that has not been captured by the analytical approach. A bifurcation and stability analysis has been carried out for different parametric variations of μ in the fluid structure interaction system.

关键词： fluid-structure interaction Bifurcation analysis Wagner's function N-S equation Limit-Cycle Oscillation Micro Air Vehicles.

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