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Adaptive mesh refinement for simulating fluid-structure interaction using a sharp interface immersed boundary method

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN fluidS 2020年第12期92卷 1890-1913页

作者： Wang, Zhuo Du, Lin Sun, Xiaofeng Beihang Univ Sch Energy & Power Engn 37 Xueyuan Rd Beijing Peoples R China

In this article, adaptive mesh refinement (AMR) is performed to simulate flow around both stationary and moving boundaries. The finite-difference approach is applied along with a sharp interface immersed boundary (IB) method. The Lagrangian polynomial is employed to facilitate the interpolation from a coarse to a fine grid level, while a weighted-average formula is used to transfer variables inversely. To save memory, the finest grid is only generated in the local areas close to the wall boundary, and the mesh is dynamically reconstructed based on the location of the wall boundary. The Navier-Stokes equations are numerically solved through the second-order central difference scheme in space and the third-order Runge-Kutta time integration. Flow around a circular cylinder rotating in a square domain is firstly simulated to examine the accuracy and convergence rate. Then three cases are investigated to test the validity of the present method: flow past a stationary circular cylinder at low Reynolds numbers, flow past a forced oscillating circular cylinder in the transverse direction at various frequencies, and a free circular cylinder subjected to vortex-induced vibration in two degrees of freedom. Computational results agree well with these in the literature and the flow fields are smooth around the interface of different refinement levels. The effect of refinement level has also been evaluated. In addition, a study for the computational efficiency shows that the AMR approach is helpful to reduce the total node number and speed up the time integration, which could prompt the application of the IB method when a great near-wall spatial resolution is required.

关键词： adaptive mesh refinement immersed boundary method fluid-structure interaction

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fluid-structure interaction assessment of blood flow hemodynamics and leaflet stress during mitral regurgitation

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COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING 2019年第3期22卷 288-303页

作者： Esfahani, Saeed Adham Hassani, Kamran Espino, Daniel M. Islamic Azad Univ Majlesi Branch Mech Engn Dept Esfahan Iran Islamic Azad Univ Sci & Res Branch Dept Biomech Tehran Iran Univ Birmingham Dept Mech Engn Birmingham W Midlands England

The aim of this study is to simulate the Mitral Regurgitation (MR) disease progression from mild to severe intensity. A fluid structure interaction (FSI) model was developed to extract the hemodynamic parameters of blood flow in mitral regurgitation (MR) during systole. A two-dimensional (2D) geometry of the mitral valve was built based on the data resulting from Magnetic Resonance Imaging (MRI) dimensional measurements. The leaflets were assumed to be elastic. Using COMSOL software, the hemodynamic parameters of blood flow including velocity, pressure, and Von Mises stress contours were obtained by moving arbitrary Lagrange-Euler mesh. The results were obtained for normal and MR cases. They showed the effects of the abnormal distance between the leaflets on the amount of returned flow. Furthermore, the deformation of the leaflets was measured during systole. The results were found to be consistent with the relevant literature.

关键词： fluid-structure interaction hemodynamics mitral regurgitation systole

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fluid-structure interaction of downwind sails: a new computational method

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JOURNAL OF MARINE SCIENCE AND TECHNOLOGY 2019年第1期24卷 86-97页

作者： Cirello, A. Cucinotta, F. Ingrassia, T. Nigrelli, V. Sfravara, F. Univ Palermo Dipartimento Innovaz Ind & Digitale Viale Sci I-90128 Palermo Italy Univ Messina I-98166 Messina Italy

The spreading of high computational resources at very low costs led, over the years, to develop new numerical approaches to simulate the fluid surrounding a sail and to investigate the fluid-structure interaction. Most methods have concentrated on upwind sails, due to the difficulty of implementing downwind sailing configurations that present, usually, the problem of massive flow separation and large displacements of the sail under wind load. For these reasons, the problem of simulating the fluid-structure interaction (FSI) on downwind sails is still subject of intensive investigation. In this paper, a new weak coupled procedure between a RANS solver and a FEM one has been implemented to study the FSI problem in downwind sailing configurations. The proposed approach is based on the progressive increasing of the wind velocity until reaching the design speed. In this way, the structural load is also applied progressively, therefore, overcoming typical convergence difficulties due to the non-linearity of the problem. Simulations have been performed on an all-purpose fractional gennaker. The new proposed method has been also compared with a classic weak FSI approach. Comparable results have been obtained in terms of flying shape of the gennaker and fluid-dynamic loads. The most significant characteristic of the proposed procedure is the easiness to find a solution in a very robust way without convergence problem, and also the capability to reduce the simulation time with regard to the computational cost.

关键词： fluid-structure interaction Finite element method Computational fluid dynamics Gennaker Mainsail Interactive sail design

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Analytical and numerical fluid-structure interaction study of a microscale piezoelectric wind energy harvester

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WIND ENERGY 2020年第6期23卷 1444-1460页

作者： Alaei, Elham Afrasiab, Hamed Dardel, Morteza Babol Noshirvani Univ Technol Mech Engn Dept Babol Sar Iran

In this paper, an analytical approach and two numerical models have been developed to study an energy-harvesting device for micropower generation. This device uses wind energy to oscillate a cantilevered beam attached to a piezoelectric layer for generating electric energy output. The analytical approach and the first numerical model consider the fluid-structure interaction phenomenon in the harvester performance. The equations governing beam oscillations and airflow have been coupled to a set of four differential equations in the analytical approach. This set of equations has been solved to determine the beam deflection and the air pressure variation with time. The numerical methods have been conducted by employing a commercial software. The results of the analytical method and the first numerical model have been compared in different working conditions, and their credibility has been discussed. In the second numerical model, the electromechanical performance of the piezoelectric material has also been incorporated in the harvester device analysis. This model has been verified against experimental data for the output voltage and power of the device available in the literature. Finally, the effect of different geometrical parameters has been studied on the harvester performance, and suggestions have been made to improve the harvester efficiency.

关键词： analytical and numerical approaches fluid-structure interaction microscale piezoelectric wind energy harvester

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A non-penetration FEM-MPM contact algorithm for complex fluid-structure interaction problems

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COMPUTERS & fluidS 2020年 213卷 104749-104749页

作者： Song, Yan Liu, Yan Zhang, Xiong Tsinghua Univ Sch Aerosp Engn Beijing 100084 Peoples R China

The improved coupled finite element material point (ICFEMP) method is an effective way to deal with fluid-structure interaction problems. However, the FEM-MPM contact algorithm employed in ICFEMP suffers from the contact penetration problem which limits its application in engineering. In this paper, the reason leading to the penetration phenomenon is revealed. The singularity of the normal vector of two adjacent surfaces makes the contact position not well-defined around at the joint line, so that particles near the joint line may penetrate the contact surface. An improved local search method is proposed in this paper to eliminate the penetration. In addition, an iterative process for imposing contact forces is proposed as well to overcome the difficulty that contact conditions can hardly be satisfied simultaneously for all contact pairs caused by the interaction among them. Numerical results illustrate that the proposed contact algorithm thoroughly eliminates the penetration phenomenon even in complex engineering problem such as the airbag simulation. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Material point method fluid-structure interaction Particle-suface contact

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A field-split preconditioning technique for fluid-structure interaction problems with applications in biomechanics

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020年第3期36卷 e3301-e3301页

作者： Calandrini, Sara Aulisa, Eugenio Ke, Guoyi Florida State Univ Dept Sci Comp 400 Dirac Sci Lib Tallahassee FL 32306 USA Texas Tech Univ Dept Math & Stat Lubbock TX 79409 USA Louisiana State Univ Alexandria Dept Math & Phys Sci Alexandria LA USA

We present a novel preconditioning technique for Krylov subspace algorithms to solve fluid-structure interaction (FSI) linearized systems arising from finite element discretizations. An outer Krylov subspace solver preconditioned with a geometric multigrid (GMG) algorithm is used, where for the multigrid level subsolvers, a field-split (FS) preconditioner is proposed. The block structure of the FS preconditioner is derived using the physical variables as splitting strategy. To solve the subsystems originated by the FS preconditioning, an additive Schwarz (AS) block strategy is employed. The proposed FS preconditioner is tested on biomedical FSI applications. Both 2D and 3D simulations are carried out considering aneurysm and venous valve geometries. The performance of the FS preconditioner is compared with that of a second preconditioner of pure domain decomposition type.

关键词： additive Schwarz preconditioner field-split preconditioner fluid-structure interaction hemodynamics

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Free vibration analysis of FGM cylindrical shells surrounded by Pasternak elastic foundation in thermal environment considering fluid-structure interaction

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APPLIED MATHEMATICAL MODELLING 2020年 78卷 550-575页

作者： Baghlani, Abdolhossein Khayat, Majid Dehghan, Seyed Mehdi Shiraz Univ Technol Dept Civil Engn & Environm Shiraz Iran

This paper presents an investigation on partially fluid-filled cylindrical shells made of functionally graded materials (FGM) surrounded by elastic foundations (Pasternak elastic foundation) in thermal environment. Material properties are assumed to be temperature dependent and radially variable in terms of volume fraction of ceramic and metal according to a simple power law distribution. The shells are reinforced by stiffeners attached to their inside and outside in which the material properties of shell and the stiffeners are assumed to be continuously graded in the thickness direction. The formulations are derived based on smeared stiffeners technique and classical shell theory using higher-order shear deformation theory which accounts for shear flexibility through shell's thickness. Displacements and rotations of the shell middle surface are approximated by combining polynomial functions in the meridian direction and truncated Fourier series with an appropriate number of harmonic terms in the circumferential direction. The governing equations of liquid motion are derived using a finite strip element formulation of incompressible inviscid potential flow. The dynamic pressure of the fluid is expanded as a power series in the radial direction. Moreover, the quiescent liquid free surface is modeled by concentric annular rings. A detailed numerical study is carried out to investigate the effects of power-law index of functional graded material, fluid depth, stiffeners, boundary conditions, temperature and geometry of the shell on the natural frequency of eccentrically stiffened functionally graded shell surrounded by Pasternak foundations. (C) 2019 Elsevier Inc. All rights reserved.

关键词： Functionally graded materials Free vibration Semi-analytical method Pasternak elastic foundation fluid-structure interaction Stiffeners

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A new formulation for fluid-structure interaction in pipes conveying fluids using Mindlin shell element and 3-D acoustic fluid element

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JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2020年第7期42卷 1-23页

作者： Krishna, Kamal R. Kochupillai, Jayaraj Coll Engn Trivandrum Adv Dynam & Control Lab Trivandrum Kerala India Govt Engn Coll Mech Engn Dept Trivandrum Kerala India

This paper explores the vibratory behavior of fluid-conveying flexible shells using a new generic finite element formulation employing the first-order shear deformation theory. The flexible tube conveying fluid is modeled using eight-noded curved Mindlin shell elements, which incorporate the effects such as shearing deformations and rotary inertia. The fluid is modeled using twenty noded isoparametric acoustic fluid elements. Solving the wave equation for an abstract scalar field velocity potential, we get the equations of motion for the fluid element. The energy transfer within the fluid and the shell is idealized with the pressure and velocity boundary conditions, which guarantees proper contact between the fluid and structure. The flexible tubes find various applications in medical as well as pharmaceutical industries. Flexible tubes demand minimal energy to excite. Hence, they can find applications in the flow measuring devices, which use vibration techniques. There is a difference in the fundamental frequencies of silicone tubes measured in the horizontal and vertical planes. This difference is due to the sagging of flexible pipes, which causes a beat phenomenon. A novel laser scanning technique is proposed to obtain the actual dimensions of flexible tubes when it sags due to gravity. This actual dimension is analyzed using the new formulation developed. The numerical results, with the actual dimensions measured using the scanning technique, give a good match with the experimental results.

关键词： fluid-structure interaction Flow through flexible pipes Natural frequency Beat phenomenon Sagging of tubes Pre-stretch Thick shells

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Simulation of cavitating fluid-structure interaction using SPH-FE method

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MATHEMATICS AND COMPUTERS IN SIMULATION 2020年第0期173卷 51-70页

作者： Kalateh, Farhoud Koosheh, Ali Univ Tabriz Fac Civil Engn Tabriz East Azerbaijan Iran

In the present paper, a modified version of SPH-FE is proposed to study the cavitating fluid interaction with the convergent- divergent nozzle. The additional terms of mass/momentum transfer, surface tension and pressure based phase change are added to the standard SPH equations to track the growth, convection and collapse of the cavitation phenomenon. Due to using the particle-based method for the fluid, no transitional phase is defined and the certain particle phase is determined by the absolute pressure value in comparison with vapor pressure. The comparison of the results of modified SPH with those of finite volume as a grid-based method shows that the cavitating region can be accurately modeled in the convergent-divergent nozzle. Then, the interaction of cavitating fluid flow-nozzle wall is simulated by the improved SPH-FE algorithm for the different types of steel where the good agreement is obtained in comparison with the other similar numerical methods. Also, it is concluded that considering cavitation in the fluid flow can generally change the nozzle behavior slightly and increase the stress values inside its body. (C) 2020 International Association for Mathematics and Computers in Simulation (IMACS). Published by Elsevier B.Y. All rights reserved.

关键词： Cavitating flow fluid-structure interaction Smoothed particle hydrodynamics (SPH) Finite element method (FEM) Immersed boundary Multi-phase fluid Phase change

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Homogenization of the fluid-structure interaction in acoustics of porous media perfused by viscous fluid

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ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK 2020年第4期71卷 137-137页

作者： Rohan, Eduard Naili, Salah Univ West Bohemia Fac Appl Sci NTIS New Technol Informat Soc Tech 8 Plzen 30100 Czech Republic Univ Paris Est Creteil CNRS MSME F-94010 Creteil France Univ Gustave Eiffel MSME F-77447 Marne La Vallee France

This paper aims to clarify the homogenization results of the fluid-structure interaction in porous structures under the quasi-static and dynamic loading regimes. In the latter case, the acoustic fluctuations yield naturally a linear model which can be introduced in the configuration deformed as the consequence of the steady permanent flow. We consider a Newtonian slightly compressible fluid under the barotropic acoustic approximation. In contrast with usual simplifications, the advection phenomenon of the Navier-Stokes equations is accounted for. The homogenization results are based on the periodic unfolding method combined with the asymptotic expansion technique which provide a straight procedure leading the local problems for corrector functions yielding the effective model parameters and the macroscopic model. We show that the local problems for the solid and fluid parts are decoupled even in the dynamic interactions including the wall shear stress on the periodic interfaces. The dynamic permeability depends on the fluid flow properties including the advection effects associated with an assumed stationary perfusion of the porous structure.

关键词： Homogenization Porous media Acoustic waves Navier-Stokes equations fluid-structure interaction Dynamic permeability Advection

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