A fluid-structure interaction model in a port-Hamiltonian representation is derived for a classical guitar. After discretization, we combine the laws of continuum mechanics for solids and fluids within a unified port-...
详细信息
A fluid-structure interaction model in a port-Hamiltonian representation is derived for a classical guitar. After discretization, we combine the laws of continuum mechanics for solids and fluids within a unified port-Hamiltonian (pH) modelling approach by adapting the equations through an appropriate coordinate transformation on the second-order level. The high-dimensionality of the resulting system is reduced by model order reduction. The article focuses on pH-systems in different state transformations, a variety of basis generation techniques as well as structure-preserving model order reduction approaches that are independent from the projection basis. As main contribution, a thorough comparison of these method combinations is conducted. In contrast to typical frequency-based simulations in acoustics, transient time simulations of the system are presented. The approach is embedded into a straightforward workflow of sophisticated commercial software modelling and flexible in-house software for multi-physics coupling and model order reduction.
Mass transport processes are known to play an important role in many fields of biomechanics such as respiratory, cardiovascular, and biofilm mechanics. In this paper, we present a novel computational model considering...
详细信息
Mass transport processes are known to play an important role in many fields of biomechanics such as respiratory, cardiovascular, and biofilm mechanics. In this paper, we present a novel computational model considering the effect of local solid deformation and fluid flow on mass transport. As the transport processes are assumed to influence neither structure deformation nor fluid flow, a sequential one-way coupling of a fluid-structure interaction (FSI) and a multi-field scalar transport model is realized. In each time step, first the non-linear monolithic FSI problem is solved to determine current local deformations and velocities. Using this information, the mass transport equations can then be formulated on the deformed fluid and solid domains. At the interface, concentrations are related depending on the interfacial permeability. First numerical examples demonstrate that the proposed approach is suitable for simulating convective and diffusive scalar transport on coupled, deformable fluid and solid domains. Copyright (c) 2014 John Wiley & Sons, Ltd.
In the paper a numerical approach to the four equation model of water hammer (WH) with fluid-structure interaction (FSI) is presented. An algorithm for numerical solution of that model in time domain based on the meth...
详细信息
In the paper a numerical approach to the four equation model of water hammer (WH) with fluid-structure interaction (FSI) is presented. An algorithm for numerical solution of that model in time domain based on the method of characteristics (MOC) is proposed. Special attention is paid to modeling of the influence of viscoelastic pipe supports. The boundary condition at the support is formulated as a differential equation of junction motion which is solved numerically concurrently with the MOC compatibility equations. Numerical simulations were done with the use of an own computer program. The tests were conducted for a model of real pipeline built in the lab and fastened with specific, complex, supporting system. The numerical results were compared to the experimental records and after some modeling and calibration quite a good agreement was achieved. Basic behaviors in the pressure records were identified and existed discrepancies were discussed and explained. The other physical model tested and preliminary analyzed in the paper is a straight pipeline fixed to the floor only with viscoelastic supports. Such a design created the possibility of significant displacements of the pipeline on the supports and thus allowing for effective testing of the influence of supports stiffness and damping properties on the WH behaviors. The specific initial conditions for that case were formulated, solved and implemented in a computer code. It was found that proper selection of support parameters may produce significant reduction of WH pressure amplitudes, mainly due to effective energy absorption and dissipation at the supports. (C) 2017 Elsevier Ltd. All rights reserved.
This paper outlines the development of a new procedure for analysing continuum mechanics problems with a particular focus on fluid-structure interaction in flexible tubes. A review of current methods of fluid-structur...
详细信息
This paper outlines the development of a new procedure for analysing continuum mechanics problems with a particular focus on fluid-structure interaction in flexible tubes. A review of current methods of fluid-structure coupling highlights common limitations of high computational cost and solution instability. It is proposed that these limitations can be overcome by an alternative approach in which both fluid and solid components are solved within a single discretized continuum domain. A single system of momentum and continuity equations is therefore derived that governs both fluids and solids and which are solved with a single mesh using finite Volume discretization schemes. The method is validated first by simulating dynamic oscillation of a clamped elastic beam. It is then applied to study the case of interest-wave propagation in highly flexible tubes-in which a predicted wave speed of 8.58 m/s falls within 2% of an approximate analytical solution. The method shows further good agreement with analytical solutions for tubes of increasing rigidity, covering a range of wave speeds from those found in arteries to that in the undisturbed fluid. Copyright (c) 2005 John Wiley & Soils, Ltd.
A Galerkin-free model reduction approach for fluid-structure interaction (FSI) is presented in this article. The reduced order model (ROM) is based on proper orthogonal decomposition (POD), where a reduced basis is fo...
详细信息
A Galerkin-free model reduction approach for fluid-structure interaction (FSI) is presented in this article. The reduced order model (ROM) is based on proper orthogonal decomposition (POD), where a reduced basis is formed using energy dominant POD modes. The reduced basis also consists of characteristics POD time modes that are derived from the POD time modes (coefficients) by using their periodicity. In addition to flow variables, the solution state vector comprises the mesh deformation, taking into account the structural deformation in FSI. A ROM solution is obtained by performing a linear interpolation of the reduced basis for changing operating/ control parameters. The proposed Galerkin-free POD-ROM approach is demonstrated in terms of two test cases: a canonical case study of vortex-induced vibration (VIV) of a cylinder at Reynolds number Re = 100, where simulations are performed for various structural-to-fluid mass ratios;and a shock wave boundary layer induced panel flutter. For the second case, we use previously computed high-fidelity simulations, considering only the effect of panel thickness on the aeroelastic coupling between the flexible panel and shock wave boundary layer interaction (SWBLI);the inflow is at Mach 2 and Reynolds number based on panel length Re-a = 50000. The presented Galerking-free ROM procedure is clean and robust for large mesh deformations, in addition to a significantly lower cost of computation compared to the FSI high-fidelity simulations. (C) 2019 Elsevier Inc. All rights reserved.
In this paper we present a fluid-structure interaction model of neuron's membrane deformation. The membrane-actin is considered as an elastic solid layer, while the cytoplasm is considered as a viscous fluid one. ...
详细信息
In this paper we present a fluid-structure interaction model of neuron's membrane deformation. The membrane-actin is considered as an elastic solid layer, while the cytoplasm is considered as a viscous fluid one. The membrane-actin layer is governed by elasticity equations while the cytoplasm is described by the Navier-Stokes equations. At the interface between the cytoplasm and the membrane we consider a match between the solid velocity displacement and the fluid velocity as well as the mechanical equilibrium. The membrane, which faces the extracellular medium, is free to move. This will change the geometry in time. To take into account the deformation of the initial configuration, we use the Arbitrary Lagrangian Eulerian method in order to take into account the mesh displacement. The numerical simulations, show the emergence of a filopodium, a typical structure in cells undergoing deformation.
We analyze a splitting method for a canonical fluidstructureinteraction problem. The splitting method uses a Robin-Robin boundary condition to define an explicit coupling between the fluid and the structure. We prov...
详细信息
We analyze a splitting method for a canonical fluidstructureinteraction problem. The splitting method uses a Robin-Robin boundary condition to define an explicit coupling between the fluid and the structure. We prove the method is stable and, furthermore, we provide an error estimate that shows the error at the final time T is O(T Delta t) where Delta t is the time step.
In this paper, we describe a three-dimensional simulation of the fluid-structure interaction (FSI) of the aortic valve using a direct-forcing immersed-boundary method. The geometry of the valve is taken from a biopros...
详细信息
In this paper, we describe a three-dimensional simulation of the fluid-structure interaction (FSI) of the aortic valve using a direct-forcing immersed-boundary method. The geometry of the valve is taken from a bioprosthetic valve, and the computational framework is based on a previous partitioned approach that is versatile for handling a range of biological FSI problems involving large deformations. When applying the approach in the heart valve simulation, we implemented an efficient parallel algorithm based on domain decomposition to handle the costly flow simulation. As compared with previous simulations of the aortic valve, our simulation was able to capture both realistic deformation of the leaflets and vortex structures in the flow, thus providing a balanced modeling approach for the flow and the valve. The results show that the pressure distribution on the leaflet surface is highly nonuniform and the jet flow contains a sequence of vortices during the opening process. After the valve is fully opened, both the three leaflets and the jet still experience significant oscillations. The drag resistance of the valve is also characterized, and it is found that the resistance is approximately equivalent to the inertial force of accelerating the fluid column of three diameter length. These details could be potentially used to characterize FSI of the aortic valve. (C) 2018 Elsevier Ltd. All rights reserved.
The numerical solution of fluid-structure interactions with the customary subiteration method incurs numerous deficiencies. We propose a novel solution method based on the conjugation of subiteration with a Newton-Kry...
详细信息
The numerical solution of fluid-structure interactions with the customary subiteration method incurs numerous deficiencies. We propose a novel solution method based on the conjugation of subiteration with a Newton-Krylov method, and demonstrate its superiority and beneficial characteristics. Copyright (c) 2004 John Wiley T Sons, Ltd.
We investigate optimization problems in which the state is given in terms of fluid-structure interactions. The coupled problem is formulated with the help of the ALE (arbitrary Lagrangian-Eulerian) mapping. The soluti...
详细信息
We investigate optimization problems in which the state is given in terms of fluid-structure interactions. The coupled problem is formulated with the help of the ALE (arbitrary Lagrangian-Eulerian) mapping. The solution approach is based on derivative-based optimization algorithms in which the derivatives are obtained with the help of the Lagrange formalism, leading to the so-called optimality system. The optimality system is then solved with Newton's method. The focus is on the proper derivation of the adjoint equations guiding the optimization formalism. Moreover, special attention is given to the adjoint information transport between the fluid and structure subproblems. Numerical tests are used to substantiate the theoretical framework.
暂无评论