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.

Using Two-Way Fluid-Structure Interaction to Study the Collapse of the Upper Airway of OSA Patients

2014 ◽  
Vol 553 ◽  
pp. 275-280 ◽  
Author(s):  
Mo Yin Zhao ◽  
Tracie J. Barber ◽  
Peter A. Cistulli ◽  
Kate Sutherland ◽  
Gary Rosengarten
Keyword(s):  
Computational Models ◽  
Treatment Success ◽  
Fluid Structure Interaction ◽  
Maximum Velocity ◽  
Upper Airway ◽  
Post Treatment ◽  
Mandibular Advancement ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Obstructive Sleep

Obstructive Sleep Apnea (OSA) is a common sleep disorder characterized by repetitive collapse of the upper airway (UA) during sleep. Treatment options for OSA include mandibular advancement splints (MAS), worn intra-orally to protrude the lower jaw to stabilize the airway. However not all patients will respond to MAS therapy and individual effects on the upper airway are not well understood. Simulations of airway behavior represent a non-invasive means to understand this disorder and treatment responses in individual patients. The aims of this study was to perform analysis of upper airway (UA) occlusion and flow dynamics in OSA using the fluid structure interaction (FSI) method, and secondly to observe changes associated with MAS usage. Magnetic resonance imaging (MRI) scans were obtained with and without mandibular advance splint (MAS) treatment in a patient known to be a treatment responder. Computational models of the anatomically correct UA geometry were reconstructed for both pre-and post-treatment (MAS) conditions. By comparing the simulation results, the treatment success of MAS was demonstrated by smaller UA structure deformation (maximum 2mm) post-treatment relative to the pre-treatment fully collapsed (maximum 6mm) counterpart. The UA collapse was located at the oropharynx and the low oropharyngeal pressure (-51 Pa to-39 Pa) was induced by the velopharyngeal jet flow (maximum 10 m/s). The results support previous OSA computational fluid dynamics (CFD) studies by indicating similar UA pressure drop and maximum velocity values. These findings lay a firm platform for the application of computational models for the study of the biomechanical properties of the upper airway in the pathogenesis and treatment of OSA.

scholarly journals B-Spline Impulse Response Functions of Rigid Bodies for Fluid-Structure Interaction Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
S. Zhou-Bowers ◽  
D. C. Rizos
Keyword(s):  
Impulse Response ◽  
Dynamic Models ◽  
Interaction Analysis ◽  
Fluid Structure Interaction ◽  
Rigid Bodies ◽  
The Body ◽  
Impulse Response Functions ◽  
Fluid Structure ◽  
B Spline ◽  
Structure Interaction

Reduced 3D dynamic fluid-structure interaction (FSI) models are proposed in this paper based on a direct time-domain B-spline boundary element method (BEM). These models are used to simulate the motion of rigid bodies in infinite or semi-infinite fluid media in real, or near real, time. B-spline impulse response function (BIRF) techniques are used within the BEM framework to compute the response of the hydrodynamic system to transient forces. Higher-order spatial and temporal discretization is used in developing the kinematic FSI model of rigid bodies and computing its BIRFs. Hydrodynamic effects on the massless rigid body generated by an arbitrary transient acceleration of the body are computed by a mere superposition of BIRFs. Finally, the dynamic models of rigid bodies including inertia effects are generated by introducing the kinematic interaction model to the governing equation of motion and solve for the response in a time-marching scheme. Verification examples are presented and demonstrate the stability, accuracy, and efficiency of the proposed technique.

scholarly journals Dealing with the Effect of Air in Fluid Structure Interaction by Coupled SPH-FEM Methods

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1162 ◽  
Author(s):  
Cristiano Fragassa ◽  
Marko Topalovic ◽  
Ana Pavlovic ◽  
Snezana Vulovic
Keyword(s):  
Finite Element Method ◽  
Smoothed Particle Hydrodynamics ◽  
Computational Models ◽  
Fluid Structure Interaction ◽  
The Finite Element Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
High Computational Complexity

Smoothed particle hydrodynamics (SPH) and the finite element method (FEM) are often combined with the scope to model the interaction between structures and the surrounding fluids (FSI). There is the case, for instance, of aircrafts crashing on water or speedboats slamming into waves. Due to the high computational complexity, the influence of air is often neglected, limiting the analysis to the interaction between structure and water. On the contrary, this work aims to specifically investigate the effect of air when merged inside the fluid–structure interaction (FSI) computational models. Measures from experiments were used as a basis to validate estimations comparing results from models that include or exclude the presence of air. Outcomes generally showed a great correlation between simulation and experiments, with marginal differences in terms of accelerations, especially during the first phase of impact and considering the presence of air in the model.

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.

MODELING OF ILIAC ARTERY ANEURYSM USING FLUID–STRUCTURE INTERACTION

2015 ◽  
Vol 15 (01) ◽  
pp. 1550041 ◽  
Author(s):  
HATEF SABOONI ◽  
KAMRAN HASSANI ◽  
HAMIDREZA GHASEMI BAHRASEMAN
Keyword(s):  
Iliac Artery ◽  
Computational Models ◽  
Fluid Structure Interaction ◽  
Artery Aneurysm ◽  
Computational Method ◽  
Discussion Section ◽  
Iliac Artery Aneurysm ◽  
Fluid Structure ◽  
Shear Rates ◽  
Structure Interaction

The aneurysm of iliac artery is a rare entity and there are few computational models that have studied the disease. In this study, we have presented the flow patterns in the aneurysmal artery using Fluid–structure interaction method. The blood was assumed Newotonian, pulsatile, laminar, incompressible, and homogenous. The geometry of the model was made based on CT images of clinical cases. Using the computational method, we have obtained the velocity and pressure contours, shear rates and vortices for the healthy and aneurysmal artery. The results show that a pressure maximum was found at the midpoint of the dilation. The vortices are formed in the aneurysmal area26 and shear rates do not change much. However, the rate increased in the neck of aneurysms. Furthermore, the aneurysm with bigger dilation tend to rupture due to more shear rates in the neck and the velocity at peak systole decreases in the aneurysmal area due to increase of the artery diameter. We have compared our results with some available relevant clinical data in discussion section.

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 Analyses of Biological Systems Using Smoothed-Particle Hydrodynamics

Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 185
Author(s):  
Milan Toma ◽  
Rosalyn Chan-Akeley ◽  
Jonathan Arias ◽  
Gregory D. Kurgansky ◽  
Wenbin Mao
Keyword(s):  
Smoothed Particle Hydrodynamics ◽  
Computational Models ◽  
Biological Systems ◽  
Fluid Structure Interaction ◽  
Disease Diagnosis ◽  
Fluid Structure ◽  
Interaction Models ◽  
Structure Interaction ◽  
Particle Hydrodynamics ◽  
Smoothed Particle

Due to the inherent complexity of biological applications that more often than not include fluids and structures interacting together, the development of computational fluid–structure interaction models is necessary to achieve a quantitative understanding of their structure and function in both health and disease. The functions of biological structures usually include their interactions with the surrounding fluids. Hence, we contend that the use of fluid–structure interaction models in computational studies of biological systems is practical, if not necessary. The ultimate goal is to develop computational models to predict human biological processes. These models are meant to guide us through the multitude of possible diseases affecting our organs and lead to more effective methods for disease diagnosis, risk stratification, and therapy. This review paper summarizes computational models that use smoothed-particle hydrodynamics to simulate the fluid–structure interactions in complex biological systems.

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