scholarly journals Numerical Investigation of Pulse Wave Propagation in Arteries Using Fluid Structure Interaction Capabilities

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Hisham Elkenani ◽  
Essam Al-Bahkali ◽  
Mhamed Souli
Keyword(s):  
Wave Propagation ◽  
Pulse Wave ◽  
Regression Line ◽  
Computing Time ◽  
Fluid Structure Interaction ◽  
Elastic Tube ◽  
Contour Plot ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Constitutive Material Model

The aim of this study is to present a reliable computational scheme to serve in pulse wave velocity (PWV) assessment in large arteries. Clinicians considered it as an indication of human blood vessels’ stiffness. The simulation of PWV was conducted using a 3D elastic tube representing an artery. The constitutive material model specific for vascular applications was applied to the tube material. The fluid was defined with an equation of state representing the blood material. The onset of a velocity pulse was applied at the tube inlet to produce wave propagation. The Coupled Eulerian-Lagrangian (CEL) modeling technique with fluid structure interaction (FSI) was implemented. The scaling of sound speed and its effect on results and computing time is discussed and concluded that a value of 60 m/s was suitable for simulating vascular biomechanical problems. Two methods were used: foot-to-foot measurement of velocity waveforms and slope of the regression line of the wall radial deflection wave peaks throughout a contour plot. Both methods showed coincident results. Results were approximately 6% less than those calculated from the Moens-Korteweg equation. The proposed method was able to describe the increase in the stiffness of the walls of large human arteries via the PWV estimates.

WALL SHEAR STRESSES IN A FLUID–STRUCTURE INTERACTION MODEL OF PULSE WAVE PROPAGATION

2014 ◽  
Vol 14 (02) ◽  
pp. 1450019 ◽  
Author(s):  
FAN HE
Keyword(s):  
Wave Propagation ◽  
Pulse Wave ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Elastic Tube ◽  
Tube Model ◽  
Pulse Wave Propagation ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Internal Radius

In our prior paper, a fluid–structure interaction model of pulse wave propagation, called the elastic tube model, has been developed. The focus of this paper is wall shear stress (WSS) in this model and the effects of different parameters, including rigid walls, wall thickness, and internal radius. The unsteady flow was assumed to be laminar, Newtonian and incompressible, and the vessel wall to be linear-elastic isotropic, and incompressible. A fluid–structure interaction scheme is constructed using a finite element method. The results demonstrate the elastic tube plays an important role in WSS distributions of wave propagation. It is shown that there is a time delay between the WSS waveforms at different locations in the elastic tube model while the time delay cannot be observed clearly in the rigid tube model. Compared with the elastic tube model, the increase of the wall thickness makes disturbed WSS distributions, however WSS values are increased greatly due to the decrease of the internal radius. The results indicate that the effects of different parameters on WSS distributions are significant. The proposed model gives valid results.

Numerical evaluation of blood viscosity affecting pulse wave propagation in a fluid-structure interaction model

2015 ◽  
Vol 60 (1) ◽  
Author(s):  
Fan He ◽  
Lu Hua ◽  
Li-jian Gao
Keyword(s):  
Wave Propagation ◽  
Blood Viscosity ◽  
Pulse Wave ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Pulse Wave Propagation ◽  
Fluid Structure ◽  
Velocity Amplitude ◽  
Structure Interaction ◽  
Wave Characteristics

AbstractHigh blood viscosity often causes cardiovascular diseases, such as hypertension, atherosclerosis and thrombosis. It is proven that blood viscosity plays an important role in cardiovascular functions. In this paper, pulse wave characteristics with normal and high blood viscosities are presented in detail to evaluate how blood viscosity affects pulse wave propagation. A fluid-structure interaction is employed to solve for pulse wave characteristics. The results show that increased blood viscosity does not change the time delay of wave propagation. However, high viscosity reduces the velocity amplitude, while it enhances the pressure level. This study provides physical insight for evaluating blood viscosity leading potentially to pulse wave changes.

A Study for Theoretical Modeling of Cavitation Inducement From the Solid-Fluid Interface With Fluid-Structure Interaction

2018 ◽  
Author(s):  
Tomohisa Kojima ◽  
Kazuaki Inaba ◽  
Yuto Takada
Keyword(s):  
Wave Propagation ◽  
Fracture Mechanics ◽  
Pressure Wave ◽  
Fluid Structure Interaction ◽  
Initial Crack ◽  
Elastic Tube ◽  
Fluid Interface ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Cavitation Intensity

A theoretical model was explored for predicting cavitation generation from a solid-fluid interface with fluid-structure interaction. Predicting cavitation generation is crucial to evaluate the lifetime of fluid machines. Cavitation has been generated from a solid-fluid interface with tensile stress (pressure) wave propagation across the interface. It was revealed that cavitation generation was suppressed when the surface wettability of the solid in a solid-fluid interface was improved (hydrophilized). It means that a condition exists in which cavitation is not generated despite the existence of bubble nuclei in water. This phenomenon cannot be explained by the conventional theory of fluid mechanics. In this study, an analogy between the theory of crack propagation in fracture mechanics and cavitation generation and propagation from a solid-fluid interface with fluid-structure interactions is developed and applied. An impact experiment was conducted with a free-falling projectile that hit a cylindrical solid buffer placed on top of a water surface within an elastic tube standing on the ground. The projectile impact created a stress wave propagating through the buffer and across the interface of the buffer and water. During the experiments, cavitation bubbles were generated from the interface of the buffer and water due to tensile wave propagation across the interface. Cavitation intensity was controlled by adding a surfactant to water. A bubble was set on the solid-fluid interface beforehand, then its growth with stress (or pressure) wave propagation was observed. The formularization of cavitation occurrence was tested by using initial crack length and stress in fracture mechanics as an analogy for the diameter of pre-set bubble and pressure wave amplitude.

scholarly journals Modeling Pulse Wave Propagation Through a Stenotic Artery With Fluid Structure Interaction: A Validation Study Using Ultrasound Pulse Wave Imaging

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Vittorio Gatti ◽  
Pierre Nauleau ◽  
Grigorios M. Karageorgos ◽  
Jay J. Shim ◽  
Gerard A. Ateshian ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wave Propagation ◽  
Arterial Wall ◽  
Pulse Wave ◽  
Fluid Structure Interaction ◽  
Clinical Findings ◽  
Pulse Wave Propagation ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wave Imaging

Abstract Pulse wave imaging (PWI) is an ultrasound-based method that allows spatiotemporal mapping of the arterial pulse wave propagation, from which the local pulse wave velocity (PWV) can be derived. Recent reports indicate that PWI can help the assessment of atherosclerotic plaque composition and mechanical properties. However, the effect of the atherosclerotic plaque's geometry and mechanics on the arterial wall distension and local PWV remains unclear. In this study, we investigated the accuracy of a finite element (FE) fluid–structure interaction (FSI) approach to predict the velocity of a pulse wave propagating through a stenotic artery with an asymmetrical plaque, as quantified with PWI method. Experiments were designed to compare FE-FSI modeling of the pulse wave propagation through a stenotic artery against PWI obtained with manufactured phantom arteries made of polyvinyl alcohol (PVA) material. FSI-generated spatiotemporal maps were used to estimate PWV at the plaque region and compared it to the experimental results. Velocity of the pulse wave propagation and magnitude of the wall distension were correctly predicted with the FE analysis. In addition, findings indicate that a plaque with a high degree of stenosis (>70%) attenuates the propagation of the pulse pressure wave. Results of this study support the validity of the FE-FSI methods to investigate the effect of arterial wall structural and mechanical properties on the pulse wave propagation. This modeling method can help to guide the optimization of PWI to characterize plaque properties and substantiate clinical findings.

A reduced mesh movement method based on pseudo elastic solid for fluid–structure interaction

2017 ◽  
Vol 232 (6) ◽  
pp. 973-986
Author(s):  
Jize Zhong ◽  
Zili Xu
Keyword(s):  
Computing Time ◽  
Fluid Structure Interaction ◽  
Elastic Solid ◽  
Continuity Condition ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Wing Flutter ◽  
Mesh Movement ◽  
Nodal Displacements ◽  
Low Order

A reduced mesh movement method based on pseudo elastic solid is developed and applied in fluid–structure interaction problems in this paper. The flow mesh domain is assumed to be a pseudo elastic solid. The vibration equation for the structure and the pseudo elastic solid together is derived by applying the displacement continuity condition on the fluid–structure interface. Considering that the actual fluid–structure coupled vibration for structures often appears to be associated with low-order modes, the nodal displacements for the structure and the flow mesh can be computed using the modal superposition of a few low-order modes. Coupled fluid–structure computations are performed for flutter problems of a beam and wing 445.6 using the present method. The calculated results are consistent with the data reported in other references. The computing time is reduced by 65.5% for the beam flutter and 54.8% for the wing flutter compared with the pre-existing elastic solid method.

Sign in / Sign up

Export Citation Format

Share Document