Multiple Reflection Theory for Fluid-Structure Interaction in Viscoelastic Vessels and Experimental Validation

2016 ◽  
Author(s):  
J. M. B. Kroot ◽  
C. G. Giannopapa
Keyword(s):  
Experimental Data ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Analytical Theory ◽  
Arterial Blood Flow ◽  
Transition Line ◽  
Multiple Reflections ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Arterial Blood

Fluid-structure interaction in viscoelastic vessels is often modelled with the motivation to understand arterial blood flow. Traveling waves in flexible vessels have been analyzed and experiments have been performed by many researchers. Theoretical models often focus either on the flow of the liquid (assuming that the wall is rigid), or on the displacement of the wall (assuming that the wall is elastic). Analytical theories on the interaction between the fluid and the wall are limited; models are typically based on numerical techniques. For assessing the validity of analytical and numerical models well-defined in-vitro experiments are of great importance. The objective of this paper is to present a transmission line analytical theory and validate it against experimental data obtained for aortic analogues. Transition line theory allows for including non-uniformities of vessels by capturing them as several uniform segments. The analytical theory is set up by multiple sections and a formulation is derived that incorporates the multiple reflections and transmissions of propagating waves through the interfaces of these sections. The pressure, flow and wall distention results obtained from the analytical model are compared with experimental data from a straight uniform tube and a tapered one with aortic relevance. The analytical results and the experimental measurements were found to be in good agreement for both the uniform and tapered tubes.

Multiple Reflection and Transmission Theory for Wave Propagation in the Aorta

2009 ◽  
Author(s):  
C. G. Giannopapa ◽  
J. M. B. Kroot
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Frequency Domain ◽  
Analytical Model ◽  
Numerical Models ◽  
Computational Cost ◽  
Arterial Blood Flow ◽  
Transition Line ◽  
One Dimensional ◽  
Arterial Blood

Wave propagation in liquid filled vessels is often motivated by the need to understand arterial blood flow. Theoretical and experimental investigations of traveling waves in flexible tubes have been performed by many researchers. The analytical one dimensional frequency domain wave theory has a great advantage of providing accurate results without the additional computational cost involved in the modern time domain simulation models. Transition line theory allows including non uniformities of vessels by capturing them as several uniform segments. For assessing the validity of analytical and numerical models well defined in-vitro experiments are of great importance. The objective of this paper is to present a frequency domain transmission line analytical model based on one-dimensional wave propagation theory and validate it against experimental data obtained for aortic analogues. The analytical model is set up by multiple sections and a formulation is derived that incorporates the multiple reflections and transmissions of propagating waves through the interfaces of these sections. The aortic analogues include straight and tapered tubes. The pressure, flow and wall distention results obtained from the analytical model are compared with experimental data in two straight tubes and one tapered one with aortic relevance. The analytical models and the experimental measurements were found to be in good agreement for both the uniform and tapered tubes.

Implicit Partitioned Fluid-Structure Interaction Coupling

2006 ◽  
Author(s):  
Michael Scha¨fer ◽  
Saim Yigit ◽  
Marcus Heck
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Finite Element ◽  
Fluid Structure Interaction ◽  
Solution Procedure ◽  
Volume Flow ◽  
Fluid Structure ◽  
Flow Solver ◽  
Solution Approach ◽  
Structure Interaction

The paper deals with an implicit partitioned solution approach for the numerical simulation of fluid-structure interaction problems. The solution procedure involves the finite-volume flow solver FASTEST, the finite-element structural solver FEAP, and the coupling interface MpCCI. The method is verified and validated by comparisons with benchmark results and experimental data. Investigations concerning the influence of the grid movement technique and an underrelaxation on the performance of the method are presented.

Composed Fluid–Structure Interaction Interface for Horizontal Axis Wind Turbine Rotor

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Dubravko Matijašević ◽  
Zdravko Terze ◽  
Milan Vrdoljak
Keyword(s):  
Wind Turbine ◽  
Numerical Models ◽  
Stress Test ◽  
Fluid Structure Interaction ◽  
Horizontal Axis ◽  
High Fidelity ◽  
Horizontal Axis Wind Turbine ◽  
Recovery Method ◽  
Fluid Structure ◽  
Structure Interaction

In this paper, we propose a technique for high-fidelity fluid–structure interaction (FSI) spatial interface reconstruction of a horizontal axis wind turbine (HAWT) rotor model composed of an elastic blade mounted on a rigid hub. The technique is aimed at enabling re-usage of existing blade finite element method (FEM) models, now with high-fidelity fluid subdomain methods relying on boundary-fitted mesh. The technique is based on the partition of unity (PU) method and it enables fluid subdomain FSI interface mesh of different components to be smoothly connected. In this paper, we use it to connect a beam FEM model to a rigid body, but the proposed technique is by no means restricted to any specific choice of numerical models for the structure components or methods of their surface recoveries. To stress-test robustness of the connection technique, we recover elastic blade surface from collinear mesh and remark on repercussions of such a choice. For the HAWT blade recovery method itself, we use generalized Hermite radial basis function interpolation (GHRBFI) which utilizes the interpolation of small rotations in addition to displacement data. Finally, for the composed structure we discuss consistent and conservative approaches to FSI spatial interface formulations.

Computational dynamic models and experiments in the fluid–structure interaction of pipe systems

2016 ◽  
Vol 43 (1) ◽  
pp. 60-72 ◽  
Author(s):  
M. Simão ◽  
J. Mora-Rodriguez ◽  
H.M. Ramos
Keyword(s):  
Computational Models ◽  
Dynamic Models ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Rheological Behaviour ◽  
Pipe Material ◽  
Expansion Joints ◽  
Fluid Structure ◽  
Pipe System ◽  
Structure Interaction

Fluid–structure interaction is analyzed using 1D and 3D computational models and results from an experimental facility, where transient events are induced. The water-hammer phenomenon is modelled by a 1D model based on the method of characteristics and the COMSOL Multiphysics 4.3b, which uses finite element method to study the fluid structural interaction involved in a long pressurized pipe system with curves, expansion joints, anchor and support blocks and different rheological behaviour of the pipe material. Comparisons are made between the experimental data and the two numerical models, where the type of response of each model was enhanced, as well as the ability of each model to simulate real conditions.

scholarly journals Wave Propagation in Thin-Walled Aortic Analogues

2008 ◽  
Author(s):  
C. G. Giannopapa ◽  
J. M. B. Kroot
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Frequency Domain ◽  
Analytical Model ◽  
Viscoelastic Properties ◽  
Numerical Models ◽  
Computational Cost ◽  
Arterial Blood Flow ◽  
One Dimensional ◽  
Arterial Blood

Research wave propagation in liquid filled vessels is often motivated by the need to understand arterial blood flow. Theoretical and experimental investigation of the propagation of waves in flexible tubes has been studied by many researchers. The analytical one dimensional frequency domain wave theory has a great advantage of providing accurate results without the additional computational cost related to the modern time domain simulation models. For assessing the validity of analytical and numerical models well defined in-vitro experiments are of great importance. The objective of this paper is to present a frequency domain transmission line analytical model based on one-dimensional wave propagation theory and validate it against experimental data obtained for aortic analogues. The elastic and viscoelastic properties of the wall are included in the analytical model. The pressure, flow and wall distention results obtained from the analytical model are compared with experimental data in two straight tubes with aortic relevance. The analytical models and the experimental measurements were found to be in good agreement when the viscoelastic properties of the wall are taken into account.

Predictive Capability of a 2D FNPF Fluid-Structure Interaction Model

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Solomon C. Yim ◽  
Huan Lin ◽  
David C. Robinson ◽  
Katsuji Tanizawa
Keyword(s):  
Free Surface ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Nonlinear Behavior ◽  
Degree Of Freedom ◽  
Surface Boundary ◽  
Predictive Capability ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Highly Nonlinear

The predictive capability of two-dimensional (2D) fully-nonlinear-potential-flow (FNPF) models of an experimental submerged moored sphere system subjected to waves is examined in this study. The experimental system considered includes both single-degree-of-freedom (SDOF) surge-only and two-degree-of-freedom (2DOF) surge-heave coupled motions, with main sources of nonlinearity from free surface boundary, large geometry, and coupled fluid-structure interaction. The FNPF models that track the nonlinear free-surface boundary exactly hence can accurately model highly nonlinear (nonbreaking) waves. To examine the predictive capability of the approximate 2D models and keep the computational effort manageable, the structural sphere is converted to an equivalent 2D cylinder. Fluid-structure interaction is coupled through an implicit boundary condition enforcing the instantaneous dynamic equilibrium between the fluid and the structure. The numerical models are first calibrated using free-vibration test results and then employed to investigate the wave-excited experimental responses via comparisons of time history and frequency response diagrams. Under monochromatic wave excitations, both SDOF and 2DOF models exhibit complex nonlinear experimental responses including coexistence, harmonics, subharmonics, and superharmonics. It is found that the numerical models can predict the general qualitative nonlinear behavior, harmonic and subharmonic responses as well as bifurcation structure. However, the predictive capability of the models deteriorates for superharmonic resonance possibly due to three-dimensional (3D) effects including diffraction and reflection. To accurately predict the nonlinear behavior of moored sphere motions in the highly sensitive response region, it is recommended that the more computationally intensive 3D numerical models be employed.

A New Way to Simulate the Fluid Structure Interaction between the Bioprosthetic Heart Valve and Blood: FE-SPH Method

2014 ◽  
Vol 472 ◽  
pp. 125-130 ◽  
Author(s):  
Quan Yuan ◽  
Xin Ye
Keyword(s):  
Heart Valve ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Peak Stress ◽  
Bioprosthetic Heart Valve ◽  
Ejection Time ◽  
Sph Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Von Mises

The object of this study is to utilize FE-SPH method to simulate the dynamic behavior of bioprosthetic heart valve during systole. Two kind of bioprosthetic heart valve numerical models are designed based on membrane theory, and they are represented by FE mesh, the blood is modelled as SPH particles. The interaction between the blood and bioprosthetic heart valve is carried out with contact algorithms. Results show that: when the valve leaflets are opening, compared with that of spherical valve, the stress and strain states of cylindrical valve are unstable, and the peak Von Mises is also higher, which high peak stress and its instability may induce the fatigue of valve. The valve opening time of columnar valve leaflets is longer than that of spherical ones, which reduces the blood ejection time. Above results indicate that spherical valve is superior to cylindrical valve. The FE-SPH method is capable of simulating the fluid structure interaction between the bioprosthetic heart valve and blood during the systole.

scholarly journals Fluid-Structure Interaction of Wind Turbine Blade Using Four Different Materials: Numerical Investigation

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1467 ◽  
Author(s):  
Rajendra Roul ◽  
Awadhesh Kumar
Keyword(s):  
Structural Analysis ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Fluid Structure Interaction ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Arterial Blood ◽  
Physical Phenomena

The interaction of a flexible system with a moving fluid gives rise to a wide variety of physical phenomena with applications in various engineering fields, such as aircraft wing stability, arterial blood progression, high structure reaction to winds, and turbine blade vibration. Both the structure and fluid need to be modeled to understand these physical phenomena. However, in line with the overall theme of this strength, the focus here is to investigate wind turbine aerodynamic and structural analysis by combining computational fluid dynamics (CFD) and finite element analysis (FEA). One-way coupling is chosen for the fluid-structure interaction (FSI) modeling. The investigation is carried out with the use of commercialized ANSYS applications. A total of eight different wind velocities and five different angles of pitch are considered in this analysis. The effect of pitch angles on the output of a wind turbine is also highlighted. The SST k-ω turbulence model has been used. A structural analysis investigation was also carried out and is carried out after importing the pressure load exerted from the aerodynamic analysis and subsequently finding performance parameters such as deformation and Von-Mises stress.

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