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fluid-structure interaction during the impact of a cylindrical shell on a thin layer of water

JOURNAL OF fluidS AND structureS 2009年第3期25卷 431-444页

作者： Khabakhpasheva, T. I. MA Lavrentyev Hydrodynam Inst Novosibirsk 630090 Russia

A two-dimensional unsteady analysis of an elastic circular cylindrical shell that enters a thin layer of an ideal incompressible liquid is considered. The cylinder initially touches the liquid free surface at a single point and then penetrates the liquid layer at a constant vertical velocity. The problem is coupled because the liquid flow, the shape of the elastic shell and the geometry of the contact region between the body and the liquid must be determined simultaneously. The flow region is subdivided into four complementary regions that exhibit different properties: the region beneath the entering body surface, the jet root, the spray jet, and the outer region. A complete solution is obtained by matching the solutions within these four subdomains. The structural analysis is based on the normal-mode method. Strain-time histories of the inner surface of the cylinder are of particular interest. In the case of a very flexible shell three distinct regimes of the impact process were found. For a high impact velocity the lower part of the shell flattens and the shell does not enter the water. For a moderate impact velocity the shell reaches the bottom and an effect of "fluid capture" may occur. For a low impact velocity the shell penetrates the liquid, but the size of the contact region decreases before the shell reaches the bottom. This behaviour corresponds to exit or "reflection" of the shell from the water layer. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： Water impact fluid-structure interaction Elastic shell Thin layer of water Normal mode method

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fluid-structure interaction simulation of pulsatile ventricular assist devices

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COMPUTATIONAL MECHANICS 2013年第5期52卷 971-981页

作者： Long, C. C. Marsden, A. L. Bazilevs, Y. Univ Calif San Diego San Diego CA 92093 USA

In this paper we present a collection of fluid-structure interaction (FSI) computational techniques that enable realistic simulation of pulsatile Ventricular Assist Devices (VADs). The simulations involve dynamic interaction of air, blood, and a thin membrane separating the two fluids. The computational challenges addressed in this work include large, buckling motions of the membrane, the need for periodic remeshing of the fluid mechanics domain, and the necessity to employ tightly coupled FSI solution strategies due to the very strong added mass effect present in the problem. FSI simulation of a pulsatile VAD at realistic operating conditions is presented for the first time. The FSI methods prove to be robust, and may be employed in the assessment of current, and the development of future, pulsatile VAD designs.

关键词： Pulsatile VAD fluid-structure interaction Isogeometric analysis Biomechanics Finite elements Blood flow Rotation-free shells

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fluid-structure interaction modeling of blood flow and cerebral aneurysm: Significance of artery and aneurysm shapes

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2009年第45-46期198卷 3613-3621页

作者： Torii, Ryo Oshima, Marie Kobayashi, Toshio Takagi, Kiyoshi Tezduyar, Tayfun E. Univ London Imperial Coll Sci Technol & Med Dept Chem Engn London SW7 2AZ England Univ Tokyo Inst Ind Sci Meguro Ku Tokyo 1538505 Japan Japan Automobile Res Inst Tsukuba Ibaraki 3050822 Japan Fujita Hlth Univ Dept Neurosurg Aichi 4701192 Japan Rice Univ Houston TX 77005 USA

Because wall shear stress (WSS) is known to play an important role in initiation, growth and rupture of cerebral aneurysm, predicting the hemodynamic forces near the aneurysmal site helps with understanding aneurysms better. Earlier research reports indicate that the WSS around the aneurysmal site has a significant relationship with the vascular and aneurysm morphology. It was also shown statistically that the aneurysm shape (aspect ratio) is an indicator of rupture risk in cerebral aneurysm. In this study, fluid-structure interaction (FSI) modeling of a ruptured aneurysm, two unruptured aneurysms at the middle cerebral artery (MCA) bifurcation, and a MCA bifurcation without aneurysm is carried out using vascular geometries reconstructed from CT images. We use pulsatile boundary conditions based on a physiological flow velocity waveform and investigate the relationship between the hemodynamic forces and vascular morphology for different arteries and aneurysms. The results are compared with the results obtained for the rigid arterial wall to highlight the role of FSI in the patient-specific modeling of cerebral aneurysm. The results show that the interaction between the blood flow and arterial deformation alters the hemodynamic forces acting on the arterial wall and the interaction strongly depends on the individual aneurysm shapes. Flow impingement on the arterial wall plays a key role in determining the interaction and hemodynamic forces. When the blood flow impinges strongly on the wall, the maximum WSS tends to decrease due to the flow-wall interaction. When the blood flows straight into an aneurysm, the flow and the resulting WSS patterns are altered both qualitatively and quantitatively. When the blood in the aneurysm is nearly stagnant, a slow flow is induced by the wall motion, which raises the minimum WSS on the aneurysmal wall. The results reinforce the importance of FSI in patient-specific analysis of cerebral aneurysms. (C) 2008 Elsevier B.V. All rights r

关键词： Cerebral aneurysm fluid-structure interaction Aneurysm morphology Wall shear stress

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fluid-structure interaction analysis of NREL phase VI wind turbine: Aerodynamic force evaluation and structural analysis using FSI analysis

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RENEWABLE ENERGY 2017年 113卷 512-531页

作者： Lee, Kyoungsoo Huque, Ziaul Kommalapati, Raghava Han, Sang-Eul Prairie View A&M Univ CEES Prairie View DC 77446 USA Prairie View A&M Univ Dept Mech Engn Prairie View DC 77446 USA Prairie View A&M Univ Dept Civil & Environm Engn Prairie View DC 77446 USA Inha Univ Sch Architecture Dept Architectural Engn Inchoen 402751 South Korea

The fluid-structure interaction (FSI) analyses were performed to obtain the structural responses of 3D wind turbine research on the National Renewable Energy Laboratory (NREL) Phase VI wind turbine using the commercial program ANSYS. The surface pressure information was imported from the results of computation fluid dynamics (CFD) which were studied in advance. To perform the structural analyses for both of FSI and blade element momentum (BEM) method, the structural model of full NREL Phase VI wind turbine were developed which is assembled by a rotor, nacelle, tower and blades. The aerodynamic forces also can be calculated from structural model by the value of reaction on rotor shaft. From those new aerodynamic evaluating process, the accuracy of FSI process which utilizing CFD results were described. And the advantages and characteristics of combination of CFD/FSI which were demonstrated by investigating the structural response of NREL Phase VI turbine for 7 wind speed cases. From the studies of structural analysis, the wind turbine can be said that it is not governed by torque force, which is the main interest in power efficiency of wind turbine, but the thrust force. Finally, the practical applicability of this methodology is discussed. (C) 2017 Published by Elsevier Ltd.

关键词： fluid-structure interaction Computational fluid dynamics National Renewable Energy Laboratory Phase VI wind turbine blade Aerodynamic force Structural analysis Wind turbine

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fluid-structure interaction using a partitioned semi-implicit predictor-corrector coupling scheme for the application of large-eddy simulation

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JOURNAL OF fluidS AND structureS 2012年 29卷 107-130页

作者： Breuer, M. De Nayer, G. Muensch, M. Gallinger, T. Wuechner, R. Univ Hamburg D-22043 Hamburg Germany Univ Erlangen Nurnberg Lehrstuhl Stromungsmech D-91058 Erlangen Germany Tech Univ Munich Lehrstuhl Stat D-80290 Munich Germany

The paper is concerned with an efficient partitioned coupling scheme developed for dynamic fluid-structure interaction problems in turbulent flows predicted by eddy-resolving schemes such as large-eddy simulation (LES). To account for the added-mass effect for high density ratios of the fluid to the structure, the semi-implicit scheme guarantees strong coupling among flow and structure, but also maintains the advantageous properties of explicit time-marching schemes often used for turbulence simulations. Thus by coupling an advanced LES code for the turbulent fluid flow with a code especially suited for the prediction of shells and membranes, an appropriate tool for the time-resolved prediction of instantaneous turbulent flows around light, thin-walled structures results. Based on an established benchmark case in laminar flow, i.e., the flow around a cylinder with an attached flexible structure at the backside, the entire methodology is analyzed thoroughly including a grid independence study. After this validation, the benchmark case is finally extended to the turbulent flow regime and predicted as a coupled FSI problem applying the newly developed scheme based on a predictor-corrector method. The entire methodology is found to be stable and robust. The turbulent flow field around the flexible structure and the deflection of the structure itself are analyzed in detail. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： fluid-structure interaction Partitioned scheme Large-eddy simulation FSI benchmark (Artificial) added-mass effect Semi-implicit scheme

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fluid-structure interaction Study of Transcatheter Aortic Valve Dynamics Using Smoothed Particle Hydrodynamics

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CARDIOVASCULAR ENGINEERING AND TECHNOLOGY 2016年第4期7卷 374-388页

作者： Mao, Wenbin Li, Kewei Sun, Wei Georgia Inst Technol Tissue Mech Lab Wallace H Coulter Dept Biomed Engn 206 Technol Enterprise Pk387 Technol Circle Atlanta GA 30313 USA Emory Univ 206 Technol Enterprise Pk387 Technol Circle Atlanta GA 30313 USA Graz Univ Technol Inst Biomech Stremayrgasse 16-2 A-8010 Graz Austria

Computational modeling of heart valve dynamics incorporating both fluid dynamics and valve structural responses has been challenging. In this study, we developed a novel fully-coupled fluid-structure interaction (FSI) model using smoothed particle hydrodynamics (SPH). A previously developed nonlinear finite element (FE) model of tran-scatheter aortic valves (TAV) was utilized to couple with SPH to simulate valve leaflet dynamics throughout the entire cardiac cycle. Comparative simulations were performed to investigate the impact of using FE-only models vs. FSI models, as well as an isotropic vs. an anisotropic leaflet material model in TAV simulations. From the results, substantial differences in leaflet kinematics between FE-only and FSI models were observed, and the FSI model could capture the realistic leaflet dynamic deformation due to its more accurate spatial and temporal loading conditions imposed on the leaflets. The stress and the strain distributions were similar between the FE and FSI simulations. However, the peak stresses were different due to the water hammer effect induced by the fluid inertia in the FSI model during the closing phase, which led to 13-28% lower peak stresses in the FE-only model compared to that of the FSI model. The simulation results also indicated that tissue anisotropy had a minor impact on hemodynamics of the valve. However, a lower tissue stiffness in the radial direction of the leaflets could reduce the leaflet peak stress caused by the water hammer effect. It is hoped that the developed FSI models can serve as an effective tool to better assess valve dynamics and optimize next generation TAV designs.

关键词： Transcatheter aortic valve fluid-structure interaction Smoothed particle hydrodynamics Finite element method Hemodynamics Bioprosthetic heart valve

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fluid-structure interaction modeling of aneurysmal conditions with high and normal blood pressures

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COMPUTATIONAL MECHANICS 2006年第4-5期38卷 482-490页

作者： Torii, Ryo Oshima, Marie Kobayashi, Toshio Takagi, Kiyoshi Tezduyar, Tayfun E. Univ London Imperial Coll Sci Technol & Med Dept Chem Engn London SW7 2AZ England Univ Tokyo Inst Ind Sci Meguro Ku Tokyo 1538505 Japan Japan Automobile Res Inst Tsukuba Ibaraki 3050822 Japan Ogura Hosp Dept Neurosurg Setagaya Ku Tokyo 1588585 Japan Rice Univ Houston TX 77005 USA

Hemodynamic factors like the wall shear stress play an important role in cardiovascular diseases. To investigate the influence of hemodynamic factors in blood vessels, the authors have developed a numerical fluid-structure interaction (FSI) analysis technique. The objective is to use numerical simulation as an effective tool to predict phenomena in a living human body. We applied the technique to a patient-specific arterial model, and with that we showed the effect of wall deformation on the WSS distribution. In this paper, we compute the interaction between the blood flow and the arterial wall for a patient-specific cerebral aneurysm with various hemodynamic conditions, such as hypertension. We particularly focus on the effects of hypertensive blood pressure on the interaction and the WSS, because hypertension is reported to be a risk factor in rupture of aneurysms. We also aim to show the possibility of FSI computations with hemodynamic conditions representing those risk factors in cardiovascular disease. The simulations show that the transient behavior of the interaction under hypertensive blood pressure is significantly different from the interaction under normal blood pressure. The transient behavior of the blood-flow velocity, and the resulting WSS and the mechanical stress in the aneurysmal wall, are significantly affected by hypertension. The results imply that hypertension affects the growth of an aneurysm and the damage in arterial tissues.

关键词： cardiovascular modeling fluid-structure interaction patient-specific computation hypertension

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fluid-structure interaction within realistic three-dimensional models of the aneurysmatic aorta as a guidance to assess the risk of rupture of the aneurysm

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MEDICAL ENGINEERING & PHYSICS 2001年第9期23卷 647-655页

作者： Di Martino, ES Guadagni, G Fumero, A Ballerini, G Spirito, R Biglioli, P Redaelli, A Politecn Milan Dept Bioengn I-20133 Milan Italy IRCCS Ctr Cardiol Vasc Unit Milan Italy IRCCS Ctr Cardiol Dept Radiol Milan Italy

Abdominal aortic aneurysm (AAA) disease is a degenerating process whose ultimate event is the rupture of the vessel wall. Rupture occurs when the stresses acting on the wall rise above the strength of the AAA wall tissue. The complex mechanical interaction between blood flow and wall dynamics in a three dimensional custom model of a patient AAA was studied by means of computational coupled fluid-structure interaction analysis. Real 3D AAA geometry is obtained from CT scans image processing. The results provide a quantitative local evaluation of the stresses due to local structural and fluid dynamic conditions. The method accounts for the complex geometry of the aneurysm, the presence of a thrombus and the interaction between solid and fluid. A proven clinical efficacy may promote the method as a tool to determine factual aneurysm risk of rupture and aid the surgeon to refer elective surgery patients. (C) 2002 Published by Elsevier Science Ltd on behalf of IPEM.

关键词： aortic aneurysm wall mechanics fluid-structure interaction

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fluid-structure interaction of a two-dimensional membrane in a flow with a pressure gradient with application to convertible car roofs

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JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS 2010年第2期98卷 65-72页

作者： Knight, J. J. Lucey, A. D. Shaw, C. T. Univ Hertfordshire Sch Engn & Technol Hatfield AL10 9AB Herts England Curtin Univ Technol Fluid Dynam Res Grp Perth WA 6845 Australia Topajka Shaw Consulting Ltd Te Anau New Zealand

The flow-induced deformation of a membrane in a flow with a pressure gradient is studied. The investigation focuses on the deformation of aerodynamically loaded convertible car roofs. A computational methodology is developed with a line-element structural model that incorporates initial slackness of the flexible roof material. The computed flow-structure interaction yields stable solutions, the flexible roof settling into static equilibrium. The interaction converges to a static deformation within 1% difference in the displacement variable after three iterations between fluid and structural codes. Reasonably accurate predictions, to within 7%, are possible using only a single iteration between the fluid and the structural codes for the model problem studied herein. However, the deformation results are shown to be highly dependent on the physical parameters that are used in the Calculation. Accurate representation of initial geometry, material properties and slackness should be found before the predictive benefits of the fluid-structure computations are sought. The iterative methodology overcomplicates the computation of deformation for the relatively small displacements encountered for the model problem studied herein. Such an approach would be better suited to applications with large amplitude displacements such as those encountered in sail design or deployment of a parachute. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Aeroelasticity Membrane fluid-structure interaction Coupling methodology Flexible surface Roof

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fluid-structure interaction analysis of a collapsible axial flow blood pump impeller and protective cage for Fontan patients

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ARTIFICIAL ORGANS 2020年第8期44卷 E337-E347页

作者： Hirschhorn, Matthew Bisirri, Evan Stevens, Randy Throckmorton, Amy L. Drexel Univ Sch Biomed Engn Sci & Hlth Syst BioCirc Res Lab 3141 Chestnut StRm 718 Philadelphia PA 19104 USA Acad Hlth Syst St Christophers Hosp Children Philadelphia PA USA

Limited donor organs and alternative therapies have led to a growing interest in the use of blood pumps as a treatment strategy for patients with single functional ventricle. The present study examines the use of collapsible and flexible impeller, cage, and diffuser designs of an axial blood pump for Fontan patients. Using one-way fluid-structure interaction (FSI) studies, the impact of blade deformation on blood damage and pump performance was investigated for flexible impellers. We evaluated biocompatible materials, including Nitinol, Bionate 80A polyurethane, and silicone for flow rates between 2.0-4.0 L/min and rotational speeds of 3000-9000 rpm. The level of deformation experienced by a cage and diffuser made of surgical stainless steel (control), Nitinol, and Bionate 80A polyurethane was also predicted using one-way FSI. The fluid pressure on the surface of the impeller, cage, and diffuser was determined using computational fluid dynamics (CFD), and then, the surface pressure was exported and used to investigate the impeller, cage, and diffuser deformation using finite element analysis. Finally, deformed impeller geometries were imported into the CFD software to determine the implication of deformation on pressure generation, blood damage index, and fluid streamlines. It was found that rotational speed, and not flow rate, is the largest determinant of impeller deformation, occurring at the blade trailing edges. The models predicted the maximum impeller deformation for Nitinol to be 40 nm, Bionate 80A polyurethane to be 106 mu m, and silicone to be 2.8 mm, all occurring at 9000 rpm. The effects of silicone deformation on performance were significant, particularly at speeds above 5000 rpm where a decrease in pressure generation of more than 10% was observed. Despite this loss, the pressure generation at 5000 rpm exceeded the level required to alleviate Fontan complications. A blood damage estimation was performed and levels remained low. The effect of significan

关键词： cardiovascular mechanics cavopulmonary assist device computational fluid dynamics finite element analysis fluid-structure interaction Fontan physiology numerical simulations

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