检索结果-内蒙古大学图书馆

FSI analysis of the blood flow and geometrical characteristics in the thoracic aorta

COMPUTATIONAL MECHANICS 2014年第4期54卷 1035-1045页

作者： Suito, Hiroshi Takizawa, Kenji Huynh, Viet Q. H. Sze, Daniel Ueda, Takuya Okayama Univ Grad Sch Environm & Life Sci Okayama 7008530 Japan Waseda Univ Waseda Inst Adv Study Dept Modern Mech Engn Shinjuku Ku Tokyo 1698050 Japan Stanford Univ Sch Med Stanford CA 94305 USA St Lukes Int Hosp Dept Radiol Tokyo 1048560 Japan

We present a fluid-structure interaction (FSI) analysis of the blood flow and geometrical characteristics in the thoracic aorta. The FSI is handled with the sequentially-coupled arterial FSI technique. The fluid mechanics equations are solved with the ST-VMS method, which is the variational multiscale version of the deforming-spatial-domain/stabilized space-time (DSD/SST) method. We focus on the relationship between the centerline geometry of the aorta and the flow field, which influences the wall shear stress distribution. The centerlines of the aorta models we use in our analysis are extracted from the CT scans, and we assume a constant diameter. Torsion-free model geometries are generated by projecting the original centerline to its averaged plane of curvature. The flow fields for the original and projected geometries are compared to examine the influence of the torsion.

关键词： Blood flow Aortic aneurysms Wall shear stress fluid-structure interaction Space-time techniques Sequential coupling

来源：评论

学校读者我要写书评

暂无评论

Computational aeroelastic investigation of a transonic limit-cycle-oscillation experiment at a transport aircraft wing model

引用

JOURNAL OF fluidS AND structureS 2014年 49卷 223-241页

作者： Stickan, Bernd Dillinger, Johannes Schewe, Guenter DLR Inst Aeroelast D-37073 Gottingen Germany

Aeroelastic measurements of a three-dimensional wing model, the so-called Aerostabil wing, were conducted in the Transonic Windtunnel Gottingen. This clean, backward-swept wing allowed the experimental investigation of limit cycle oscillations in a certain transonic parameter range. In this paper, a detailed insight into the observed physical phenomena, especially the measured limit cycle oscillations, is presented by means of CFD-CSM coupled simulations. These simulations on the basis of a detailed structural finite element model reveal the specific properties of the Aerostabil wing and furthermore allow investigating the unstable behavior of this windtunnel model for transonic flow settings. The aerodynamic characteristics include a two-shock system and large flow separation areas, further increasing the complexity of the aeroelastic problem. A structural single degree-of-freedom system is used for the prediction of the experimental stability range and the limit cycle oscillation investigations. Due to the good agreement of simulation and experiment the limit cycle oscillations can be explained by means of nonlinear aerodynamic effects. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Aerostabil Limit-cycle oscillations fluid-structure interaction Transonic flow Single degree-of-freedom flutter Unsteady aerodynamics Static aeroelasticity

来源：评论

学校读者我要写书评

暂无评论

Aeroelastic study of flexible flapping wings by a coupled lattice Boltzmann-finite element approach with immersed boundary method

引用

JOURNAL OF fluidS AND structureS 2014年 49卷 516-533页

作者： De Rosis, Alessandro Falcucci, Giacomo Ubertini, Stefano Ubertini, Francesco Univ Bologna Dept Agr Sci DIPSA I-40127 Bologna Italy Univ Naples Parthenope Dept Technol I-80143 Naples Italy Univ Tuscia Sch Ind Engn Dept Econ & Enterprise DEIM I-01100 Viterbo Italy Univ Bologna Dept Civil Environm & Mat Engn DICAM I-40136 Bologna Italy

In this paper, the behavior of two-dimensional symmetric flapping wings moving in a viscous fluid is investigated. Harmonic motion is applied to idealize flying organisms with flexible wings and extensive testing is carried out to investigate the resultant flight behavior related to the ability to take-off or accelerate the flapping wing system away from a starting location. Special attention is paid to analyze the effect of the main mechanical parameters, as well as the effect of lateral wind on flight performances. Moreover, aiming to investigate the possible benefits of flying in flocks, a couple of synchronously flapping wings is considered in addition to the single arrangement. The numerical simulations are performed by solving the fluid-structure interaction problem through a strongly coupled partitioned approach. fluid dynamics are modeled at the mesoscopic scale by the lattice Boltzmann method. The resulting macroscopic quantities are derived, as usual, based on the statistical molecular-level interpretation. Wings are modeled by geometrically nonlinear, elastic beam finite elements and structure dynamics is solved by the time discontinuous Galerldn method. fluid-structure interface conditions are handled using the immersed boundary method. The resultant numerical approach combines simplicity and high computational efficiency. A Monte Carlo simulation strategy is employed to characterize the flight behavior subjected to lateral wind. Various scenarios are discussed. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： fluid-structure interaction Lattice Boltzmann method Flapping wings Immersed boundary

来源：评论

学校读者我要写书评

暂无评论

Numerical modal analysis of composite structures coupled with water

引用

COMPOSITE structureS 2014年第1期116卷 325-335页

作者： Kwon, Y. W. Plessas, S. D. Naval Postgrad Sch Dept Mech & Aerosp Engn Monterey CA 93943 USA

Dynamic characteristics of polymer composite beam and plate structures were studied when the structures were coupled with water. The effect of fluid-structure interaction (FSI) on natural frequencies, mode shapes, and dynamic responses was examined for polymer composite structures using multiphysics-based computational techniques. Composite structures were modeled using the Finite Element Method. The fluid was modeled as an acoustic medium using the Cellular Automata and finite element techniques. Those techniques were coupled so that both fluid and structure could interact bi-directionally. In order to make the coupling easier, the beam and plate finite elements have only displacement degrees of freedom but no rotational degrees of freedom. Then, the numerical modal analysis technique was applied to the composite structures with and without FSI, respectively, so that the effect of FSI can be examined by comparing the two results. The study showed that the effect of FSI is significant on dynamic properties of polymer composite structures. Some previous experimental observations were confirmed using the numerical modal analysis. Published by Elsevier Ltd.

关键词： fluid-structure interaction Modal analysis Multiphysics analysis

来源：评论

学校读者我要写书评

暂无评论

Multiscale methods for gore curvature calculations from FSI modeling of spacecraft parachutes

引用

COMPUTATIONAL MECHANICS 2014年第6期54卷 1461-1476页

作者： Takizawa, Kenji Tezduyar, Tayfun E. Kolesar, Ryan Boswell, Cody Kanai, Taro Montel, Kenneth Waseda Univ Dept Modern Mech Engn Shinjuku Ku Tokyo 1698050 Japan Waseda Univ Waseda Inst Adv Study Shinjuku Ku Tokyo 1698050 Japan Rice Univ Houston TX 77005 USA

There are now some sophisticated and powerful methods for computer modeling of parachutes. These methods are capable of addressing some of the most formidable computational challenges encountered in parachute modeling, including fluid-structure interaction (FSI) between the parachute and air flow, design complexities such as those seen in spacecraft parachutes, and operational complexities such as use in clusters and disreefing. One should be able to extract from a reliable full-scale parachute modeling any data or analysis needed. In some cases, however, the parachute engineers may want to perform quickly an extended or repetitive analysis with methods based on simplified models. Some of the data needed by a simplified model can very effectively be extracted from a full-scale computer modeling that serves as a pilot. A good example of such data is the circumferential curvature of a parachute gore, where a gore is the slice of the parachute canopy between two radial reinforcement cables running from the parachute vent to the skirt. We present the multiscale methods we devised for gore curvature calculation from FSI modeling of spacecraft parachutes. The methods include those based on the multiscale sequentially-coupled FSI technique and using NURBS meshes. We show how the methods work for the fully-open and two reefed stages of the Orion spacecraft main and drogue parachutes.

关键词： Spacecraft parachutes Gore curvature fluid-structure interaction Multiscale methods Sequentially-coupled FSI NURBS meshes Orion main parachutes Orion drogue parachutes Reefed stages

来源：评论

学校读者我要写书评

暂无评论

FSI: implementation, validation and industrial applications

引用

PROGRESS IN COMPUTATIONAL fluid DYNAMICS 2014年第1期14卷 49-56页

作者： Hallwachs, Dominic Heinz, Matthias Grashof, Hendrik TECOSIM GmbH D-65428 Russelsheim Germany

Through advances in computational power and solution algorithms over recent decades computational fluid dynamics (CFD) as well as computational structure dynamics (CSD) have become an integral part of product development and optimisation in the industry. The maturity of these technologies allows for the exploration of new, more complicated fields of application, specifically coupled multiphysics simulations. While the technologies exist, they have not yet seen widespread use outside of academia and specialised industries. In this paper we will present multiple code-coupling procedures, including temperature profile transferal, coupling with 1D solvers and full-fledged code-couplings that have been applied successfully in practice at TECOSIM GmbH.

关键词： fluid-structure interaction FSI partitioned staggered thermo-mechanical strongly coupled multiphysics fluid-structure

来源：评论

学校读者我要写书评

暂无评论

Resonance of Free-Surface Waves Provoked by Floodgate Maneuvers

引用

JOURNAL OF HYDROLOGIC ENGINEERING 2014年第6期19卷 1124-1130页

作者： Triki, Ali Univ Sfax Engn Sch Sfax Sfax 3038 Tunisia

Prediction of damage caused by floodgate maneuvers is treated by the determination of factors amplifying the magnitude of generated damage. The identification of vulnerable areas is obtained by analogy with the water-hammer phenomenon in pressurized pipes. The numerical model is based on the Boussinesq assumption for transient flow in open channels and solved by the Mac-Cormack scheme. Transient flow concerns a rectangular channel where the initial steady state is uniform. Transient regime is provoked by the movement of a floodgate at the upstream extremity of the channel producing sinusoidal fluctuations of depth. A condition of floodgate closure is imposed at the downstream extremity. The applied excitation has permitted analysis of the fluid structure interaction, examination of pulsations provoking the resonance of the free-surface waves, and study of the evolution of depths according to time along the channel. According to the frequency of the movement of the floodgate at the upstream end, distortion of depth profiles or oscillations over these profiles may appear. The frequency value also has a significant effect on the flow depth evolution and can provoke the flooding of the channel.

关键词： fluid-structure interactions Boussinesq equations Surface waves Resonance Wave propagation fluid-structure interaction Boussinesq assumption Free-surface wave Prismatic channel Mac-Cormack scheme Resonance Wave propagation

来源：评论

学校读者我要写书评

暂无评论

Slender-body theory for viscous flow via dimensional reduction and hyperviscous regularization

引用

MECCANICA 2014年第9期49卷 2153-2167页

作者： Giusteri, Giulio G. Fried, Eliot Univ Cattolica Sacro Cuore Dipartimento Matemat & Fis N Tartaglia I-25121 Brescia Italy Okinawa Inst Technol Grad Univ Math Soft Matter Unit Onna Son Okinawa 9040495 Japan

A new slender-body theory for viscous flow, based on the concepts of dimensional reduction and hyperviscous regularization, is presented. The geometry of flat, elongated, or point-like rigid bodies immersed in a viscous fluid is approximated by lower-dimensional objects, and a hyperviscous term is added to the flow equation. The hyperviscosity is given by the product of the ordinary viscosity with the square of a length that is shown to play the role of effective thickness of any lower-dimensional object. Explicit solutions of simple problems illustrate how the proposed method is able to represent with good approximation both the velocity field and the drag forces generated by rigid motions of the immersed bodies, in analogy with classical slender-body theories. This approach has the potential to open up the way to more effective computational techniques, since geometrical complexities can be significantly reduced. This, however, is achieved at the expense of involving higher-order derivatives of the velocity field. Importantly, both the dimensional reduction and the hyperviscous regularization, combined with suitable numerical schemes, can be used also in situations where inertia is not negligible.

关键词： Slender-body theory Hyperviscosity fluid-structure interaction Dimensional reduction

来源：评论

学校读者我要写书评

暂无评论

FEM/wideband FMBEM coupling for structural-acoustic design sensitivity analysis

引用

COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2014年 276卷 1-19页

作者： Chen, Leilei Zheng, Changjun Chen, Haibo Univ Sci & Technol China GAS Key Lab Mech Behav & Design Mat Dept Modern Mech Hefei 230026 Anhui Peoples R China

A coupling algorithm based on the finite element method (FEM) and the wideband fast multipole boundary element method (wideband FMBEM) is proposed for acoustic fluid-structure interaction simulation and structural-acoustic design sensitivity analysis by using the direct differentiation method. The wideband fast multipole method (FMM), which is developed by combining the original FMM and the diagonal form FMM, is used to accelerate the calculation of the matrix vector products in boundary element analysis. The iterative solver generalized minimal residual method is applied to accelerate the calculation of the solution to the linear system of equations. The FEM/wideband FMBEM algorithm makes it possible to predict the effects of arbitrarily shaped vibrating structures on the sound field numerically. Numerical examples are presented to demonstrate the validity and efficiency of the proposed algorithm. (C) 2014 Elsevier B.V. All rights reserved.

关键词： fluid-structure interaction FEM Wideband FMBEM Design sensitivity analysis Direct differentiation method

来源：评论

学校读者我要写书评

暂无评论

An analysis of a new stable partitioned algorithm for FSI problems. Part I: Incompressible flow and elastic solids

引用

JOURNAL OF COMPUTATIONAL PHYSICS 2014年 269卷 108-137页

作者： Banks, J. W. Henshaw, W. D. Schwendeman, D. W. Lawrence Livermore Natl Lab Ctr Appl Sci Comp Livermore CA 94551 USA Rensselaer Polytech Inst Dept Math Sci Troy NY 12180 USA

Stable partitioned algorithms for fluid-structure interaction (FSI) problems are developed and analyzed in this two-part paper. Part I describes an algorithm for incompressible flow coupled with compressible elastic solids, while Part II discusses an algorithm for incompressible flow coupled with structural shells. Importantly, these new added-mass partitioned (AMP) schemes are stable and retain full accuracy with no sub-iterations per time step, even in the presence of strong added-mass effects (e.g. for light solids). The numerical approach described here for bulk compressible solids extends the scheme of Banks et al. [1,2] for inviscid compressible flow, and uses Robin (mixed) boundary conditions with the fluid and solid solvers at the interface. The basic AMP Robin conditions, involving a linear combination of velocity and stress, are determined from the outgoing solid characteristic relation normal to the fluid solid interface combined with the matching conditions on the velocity and traction. Two alternative forms of the AMP conditions are then derived depending on whether the fluid equations are advanced with a fractional-step method or not. The stability and accuracy of the AMP algorithm is evaluated for linearized FSI model problems;the full nonlinear case being left for future consideration. A normal mode analysis is performed to show that the new AMP algorithm is stable for any ratio of the solid and fluid densities, including the case of very light solids when added-mass effects are large. In contrast, it is shown that a traditional partitioned algorithm involving a Dirichlet-Neumann coupling for the same FSI problem is formally unconditionally unstable for any ratio of densities. Exact traveling wave solutions are derived for the FSI model problems, and these solutions are used to verify the stability and accuracy of the corresponding numerical results obtained from the AMP algorithm for the cases of light, medium and heavy solids. (C) 2014 Elsevier Inc

关键词： fluid-structure interaction Partitioned algorithms Added mass instability Incompressible fluid flow Elastic solids

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：