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Shape optimization to improve the transonic fluid-structure interaction stability by an aerodynamic unsteady adjoint method

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AEROSPACE SCIENCE AND TECHNOLOGY 2020年 103卷 105871-105871页

作者： Chen, Wengang Gao, Chuanqiang Gong, Yiming Zhang, Weiwei Natl Key Lab Sci & Technol Aerodynam Design & Res Xian 710072 Peoples R China Northwestern Polytech Univ Sch Aeronaut Xian 710072 Peoples R China

A kind of single degree-of-freedom (SDOF) flutter, which is also called transonic buzz, would appear on the aircraft control surface in a specific transonic state. Engineers deal with control surface buzz mainly by improving the stiffness or damping of the structure. Traditional adjoint-based aerodynamic shape optimizations mainly focus on the aircraft aerodynamic performance. In this paper, the unsteady adjoint method is employed to improve the transonic fluid-structure interaction (FSI) stability from the viewpoint of aerodynamic shape optimization. To achieve this aim, the aerodynamic damping derivative, which represents the work done by flow to structure, is adopted as the objective of shape optimization. Results show that through the airfoil shape optimization, the FSI stability of the control surface is remarkably improved, and the buzz is eliminated successfully in design conditions. In addition, the aerodynamic performance of the control surface is also refined. (C) 2020 Elsevier Masson SAS. All rights reserved.

关键词： Unsteady adjoint method fluid-structure interaction Single degree-of-freedom flutter Stability Shape optimization

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fluid-structure interaction Vibration Response Analysis of the Hydrocyclone Under Periodic Excitation

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IEEE ACCESS 2019年 7卷 146273-146281页

作者： Li, Sen Li, Ruoning Wang, Zunce Xu, Dekui Yan, Yuejuan Xu, Yan Li, Jingshuai Chen, Xing Northeast Petr Univ Mech Sci & Engn Coll Daqing 163318 Peoples R China Heilongjiang Key Lab Petr & Petrochem Multiphase Daqing 163318 Peoples R China Daqing Oilfield Prod Engn & Res Inst Daqing 163453 Peoples R China

Considering that the hydrocyclone will be affected by internal and external fluid forces in practical work, the numerical simulation method of fluid-structure interaction(FSI) of the hydrocyclone is proposed, and the finite volume method is used in the fluid domain and the finite element method is used in the solid domain. According to the numerical simulation of the flow around a circular cylinder, the magnitude and frequency of fluid flow around the hydrocyclone are obtained. On this basis, the numerical simulation and experimental research of the hydrocyclone are carried out, and the vibration characteristic of the hydrocyclone under the FSI condition is discussed, which the modal frequencies and modes of the hydrocyclone, the structural displacement and stress distribution characteristics of the FSI interface under periodic excitation are obtained. The results of numerical simulation and measured are compared and analyzed. The distribution trend and position of the maximum acceleration values are in good agreement between the measured and numerical simulation. The maximum deformation and the maximum acceleration values position of the hydrocyclone structure which is near the intersection between small conical section and tail pipe, and the structural deformation and maximum acceleration values of the hydrocyclone increase with the increase of inlet velocity. The analysis shows that the FSI model of the hydrocyclone is reasonable. Moreover, the influencing factors of fluid flow around the hydrocyclone should be considered in the future design and application of the hydrocyclone.

关键词： Vibration modal analysis fluid-structure interaction hydrocyclone periodic excitation

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Investigation on the effect of density ratio on the convergence behavior of partitioned method for fluid-structure interaction simulation

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JOURNAL OF fluidS AND structureS 2020年 96卷 103050-103050页

作者： Ha, Sang Truong Choi, Hyoung Gwon Seoul Natl Univ Sci & Technol Dept Mech Engn Seoul South Korea Seoul Natl Univ Sci & Technol Dept Mech & Automot Engn Seoul South Korea

In order to investigate the effect of density ratio of fluid and solid on the convergence behavior of partitioned FSI algorithm, three strong-coupling partitioned algorithms (fixed-point method with a constant under-relaxation parameter, Aitken's method and Quasi-Newton inverse least squares (QN-ILS) method) have been considered in the context of finite element method. We have employed the incompressible Navier-Stokes equations for a Newtonian fluid domain and the total Lagrangian formulation for a nonlinear motion of solid domain. Linear-elastic (hyper-elastic) model has been employed for solid material with small (large) deformation. A pulsatile inlet-flow interacting with a 2D circular channel of linear-elastic material and a pressure wave propagation in a 3D flexible vessel have been simulated. Both linear-elastic and hyper-elastic (Mooney-Rivlin) models have been adopted for the 3D flexible vessel. From the present numerical experiments, we have found that QN-ILS outperforms the others leading to a robust convergence regardless of the density ratio for both linear-elastic and hyper-elastic models. On the other hand, the performances of the fixed-point method with a constant under-relaxation parameter and the Aitken's method depend strongly on the density ratio, relaxation parameter selected for coupling iteration, and degree of deformation. Although the QN-ILS of this work is still slower than a monolithic method for serial computation, it has an advantage of easier parallelization due to the modularity of the partitioned FSI algorithm. (C) 2020 Published by Elsevier Ltd.

关键词： fluid-structure interaction Strong-coupling partitioned algorithm Finite element method Density ratio Mooney-Rivlin model

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Discontinuous galerkin method for the solution of fluid-structure interaction problems with applications to the vocal folds vibration 14th

Discontinuous galerkin method for the solution of fluid-stru...

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14th International Conference on Vibration Problems, ICOVP 2019

作者： Balázsová, Monika Feistauer, Miloslav Horáček, Jaromír Kosík, Adam Faculty of Mathematics and Physics Charles University Sokolovská 83 186 75 Praha 8 Prague Czech Republic Institute of Thermomechanics of the Czech Academy of Sciences Dolejškova 5 182 00 Praha 8 Prague Czech Republic Institute for Computational Engineering University of Applied Sciences of Technology NTB Buchs Werdenbergstrasse 4 Buchs9471 Switzerland

ISBN: (纸本)9789811580482

The goal of this paper is the numerical simulation of vocal folds vibration excited by compressible viscous flow. It is necessary to describe the flow by the compressible Navier-Stokes equations in a time-dependent domain, solved by the ALE method. The vibrations of the vocal folds are modelled by the nonlinear dynamic St. Venant-Kirchhoff elasticity theory. For the flow problem we employ the discretization by the space-time discontinuous Galerkin method (STDGM) and for the elasticity problem the backward difference formula in time and discontinuous Galerkin method in space (BDF-DGM). The flow and elasticity problems are strongly coupled. We show that it is more appropriate to use the nonlinear elasticity model in contrast to linear elasticity model. © Springer Nature Singapore Pte Ltd. 2021.

关键词： ALE method Compressible flow Dynamic elasticity fluid-structure interaction Simulation of vocal fold vibration St. Venant-Kirchhoff model Time-dependent domain Vibrations of elastic structures

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On the role of (weak) compressibility for fluid-structure interaction solvers

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN fluidS 2020年第2期92卷 129-147页

作者： La Spina, Andrea Foerster, Christiane Kronbichler, Martin Wall, Wolfgang A. Tech Univ Munich Inst Computat Mech Boltzmannstr 15 D-85748 Garching Germany

In the present study, a weakly compressible formulation of the Navier-Stokes equations is developed and examined for the solution of fluid-structure interaction (FSI) problems. Newtonian viscous fluids under isothermal conditions are considered, and the Murnaghan-Tait equation of state is employed for the evaluation of mass density changes with pressure. A pressure-based approach is adopted to handle the low Mach number regime, ie, the pressure is chosen as primary variable, and the divergence-free condition of the velocity field for incompressible flows is replaced by the continuity equation for compressible flows. The approach is then embedded into a partitioned FSI solver based on a Dirichlet-Neumann coupling scheme. It is analytically demonstrated how this formulation alleviates the constraints of the instability condition of the artificial added mass effect, due to the reduction of the maximal eigenvalue of the so-called added mass operator. The numerical performance is examined on a selection of benchmark problems. In comparison to a fully incompressible solver, a significant reduction of the coupling iterations and the computational time and a notable increase in the relaxation parameter evaluated according to Aitken's Delta(2) method are observed.

关键词： artificial added mass effect Dirichlet-Neumann partitioning finite element method fluid-structure interaction weakly compressible flow

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A partition of unity approach to fluid mechanics and fluid-structure interaction

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2020年第0期362卷 112842-000页

作者： Balmus, Maximilian Massing, Andre Hoffman, Johan Razavi, Reza Nordsletten, David A. Kings Coll London Kings Hlth Partners Sch Imaging Sci & Biomed Engn Dept Biomed Engn London SE1 7EH England Umea Univ Dept Math & Math Stat SE-90187 Umea Sweden Norwegian Univ Sci & Technol Dept Math Sci NO-7491 Trondheim Norway KTH Royal Inst Technol Div Computat Sci & Technol Stockholm Sweden Univ Michigan Dept Biomed Engn & Cardiac Surg Ann Arbor MI 48109 USA

For problems involving large deformations of thin structures, simulating fluid-structure interaction (FSI) remains a computationally expensive endeavour which continues to drive interest in the development of novel approaches. Overlapping domain techniques have been introduced as a way to combine the fluid-solid mesh conformity, seen in moving-mesh methods, without the need for mesh smoothing or re-meshing, which is a core characteristic of fixed mesh approaches. In this work, we introduce a novel overlapping domain method based on a partition of unity approach. Unified function spaces are defined as a weighted sum of fields given on two overlapping meshes. The method is shown to achieve optimal convergence rates and to be stable for steady-state Stokes, Navier-Stokes, and ALE Navier-Stokes problems. Finally, we present results for FSI in the case of 2D flow past an elastic beam simulation. These initial results point to the potential applicability of the method to a wide range of FSI applications, enabling boundary layer refinement and large deformations without the need for re-meshing or user-defined stabilization. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Finite element methods fluid-structure interaction Overlapping domains Partition of unity

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L^p-theory for a fluid-structure interaction model

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ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK 2020年第5期71卷 158-158页

作者： Denk, Robert Saal, Juergen Univ Konstanz Fachbereich Math & Stat D-78457 Constance Germany Heinrich Heine Univ Dusseldorf Math Inst Angew Anal D-40204 Dusseldorf Germany

We consider a fluid-structure interaction model for an incompressible fluid where the elastic response of the free boundary is given by a damped Kirchhoff plate model. Utilizing the Newton polygon approach, we first prove maximal regularity in L-p-Sobolev spaces for a linearized version. Based on this, we show existence and uniqueness of the strong solution of the nonlinear system for small data.

关键词： fluid-structure interaction maximal regularity Newton polygon

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fluid-structure interaction of a large ice sheet in waves

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OCEAN ENGINEERING 2019年 182卷 102-111页

作者： Huang, Luofeng Ren, Kang Li, Minghao Tukovic, Zeljko Cardiff, Philip Thomas, Giles UCL Dept Mech Engn London England Chalmers Univ Technol Dept Mech & Maritime Sci Gothenburg Sweden Univ Zagreb Fac Mech Engn & Naval Architecture Zagreb Croatia Univ Coll Dublin Sch Mech & Mat Engn Dublin Ireland

With global warming, the ice-covered areas in the Arctic are being transformed into open water. This provides increased impetuses for extensive maritime activities and attracts research interests in sea ice modelling. In the polar region, ice sheets can be several kilometres long and subjected to the effects of ocean waves. As its thickness to length ratio is very small, the wave response of such a large ice sheet, known as its hydroelastic response, is dominated by an elastic deformation rather than rigid body motions. In the past 25 years, sea ice hydroelasticity has been widely studied by theoretical models;however, recent experiments indicate that the ideal assumptions used for these theoretical models can cause considerable inaccuracies. This work proposes a numerical approach based on OpenFOAM to simulate the hydroelastic wave-ice interaction, with the Navier-Stokes equations describing the fluid domain, the St. Venant Kirchhoff solid model governing the ice deformation and a coupling scheme to achieve the fluid-structure interaction. Following validation against experiments, the proposed model has been shown capable of capturing phenomena that have not been included in current theoretical models. In particular, the developed model shows the capability to predict overwash, which is a ubiquitous polar phenomenon reported to be a key gap. The present model has the potential to be used to study wave-ice behaviours and the coupled wave-ice effect on marine structures.

关键词： fluid-structure interaction Hydroelasticity Sea ice Ocean surface wave Overwash OpenFOAM

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Analysis of shape optimization problems for unsteady fluid-structure interaction

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INVERSE PROBLEMS 2020年第3期36卷 034001-034001页

作者： Haubner, Johannes Ulbrich, Michael Ulbrich, Stefan Tech Univ Munich Dept Math Boltzmannstr 3 D-85748 Garching Germany Tech Univ Munich Chair Math Optimizat Dept Math Boltzmannstr 3 D-85748 Garching Germany Tech Univ Darmstadt Dept Math Dolivostr 15 D-64293 Darmstadt Germany

Shape optimization via the method of mappings is investigated for unsteady fluid-structure interaction (FSI) problems that couple the Navier-Stokes equations and the Lame system. Building on recent existence and regularity theory we prove Frechet differentiability results for the state with respect to domain variations. These results form an analytical foundation for optimization und inverse problems governed by FSI systems. Our analysis develops a general framework for deriving local-in-time continuity and differentiability results for parameter dependent nonlinear systems of partial differential equations. The main part of the paper is devoted to conducting this analysis for the FSI problem, transformed to a shape reference domain. The underlying shape transformation-actually we work with the corresponding shape displacement instead-represents the shape and the main result proves the Frechet differentiability of the solution of the FSI system with respect to the shape transformation.

关键词： fluid-structure interaction shape optimization Frechet differentiability method of mappings Navier-Stokes equations Lame system shape identification

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Numerical model for the fluid-structure interaction mechanics of a suspended flexible body

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OCEAN ENGINEERING 2020年第0期195卷 106723-000页

作者： Ueda, Tatsuyuki Nishi, Yoshiki Yokohama Natl Univ Fac Engn Dept Syst Design Ocean Space 79-5 Tokiwadai Yokohama Kanagawa Japan

This study investigates the dynamic vibration and static deformation of a long flexible underwater body suspended from the ocean surface. A numerical model is constructed by considering (i) the structural mechanics, (ii) hydrodynamic forces induced by vortex shedding, (iii) motion mechanics associated with the free bottom end of the suspended body, and (iv) the interactions among (i)-(iii). Numerical computations are performed by applying uniform vertical distributions of the ocean flow speed and a sheared distribution, and by varying the weight of the body at the free bottom end. Comparing the computed results of these cases elucidates the mechanics of the fluid-structure interaction of the suspended body. In particular, the sheared flow velocity profile allows the growth of multiple frequency components of vibrations in the flexible body. The frequency multiplicity at a point in the body arises from the vortex-induced vibrations excited at that point, and those that are excited in other regions then propagate to that point.

关键词： fluid-structure interaction Suspended body Vortex-induced vibration Wake oscillator model Numerical model

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