scholarly journals Waves and fluid–solid interaction in stented blood vessels

2018 ◽  
Vol 474 (2209) ◽  
pp. 20170670 ◽  
Author(s):  
S. Frecentese ◽  
L. P. Argani ◽  
A. B. Movchan ◽  
N. V. Movchan ◽  
G. Carta ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Simulations ◽  
Blood Vessels ◽  
Wave Reflection ◽  
Transient Regime ◽  
Strong Variation ◽  
Structure Interaction ◽  
Time Harmonic ◽  
Fluid Solid Interaction ◽  
Repetitive Pattern

This paper focuses on the modelling of fluid–structure interaction and wave propagation problems in a stented artery. Reflection of waves in blood vessels is well documented in the literature, but it has always been linked to a strong variation in geometry, such as the branching of vessels. The aim of this work is to detect the possibility of wave reflection in a stented artery due to the repetitive pattern of the stents. The investigation of wave propagation and possible blockages under time-harmonic conditions is complemented with numerical simulations in the transient regime.

Asymmetric Wave Propagation in an Elastic Half-Space by a Method of Potentials

1987 ◽  
Vol 54 (1) ◽  
pp. 121-126 ◽  
Author(s):  
R. Y. S. Pak
Keyword(s):  
Wave Propagation ◽  
Dynamic Response ◽  
Half Space ◽  
Elastic Half Space ◽  
Displacement Potential ◽  
Uniform Distributions ◽  
Time Harmonic ◽  
Method Of Potentials ◽  
Transformed Stress ◽  
Asymmetric Wave

A method of potentials is presented for the derivation of the dynamic response of an elastic half-space to an arbitrary, time-harmonic, finite, buried source. The development includes a set of transformed stress-potential and displacement-potential relations which are apt to be useful in a variety of wave propagation problems. Specific results for an embedded source of uniform distributions are also included.

The numerical analysis of fluid-solid interactions for blood flow in arterial structures Part 2: Development of coupled fluid-solid algorithms

1998 ◽  
Vol 212 (4) ◽  
pp. 241-252 ◽  
Author(s):  
S Z Zhao ◽  
X Y Xu ◽  
M W Collins
Keyword(s):  
Blood Flow ◽  
Wave Propagation ◽  
Numerical Analysis ◽  
Blood Vessels ◽  
Applied Mechanics ◽  
Specific Topic ◽  
Numerical Techniques ◽  
Wall Effects ◽  
Clinical Context ◽  
Local Flow

In this paper, the authors extend their study of wall mechanics given in Part 1 to the overall problem of fluid-solid interactions in arterial flows. Fluid-solid coupling has become a specific topic in computational methods and applied mechanics. In this review, firstly, the effects of elasticity of blood vessels on wave propagation and local flow patterns in large arteries are discussed. Then, numerical techniques are reviewed together with the alternative coupled methods available in fluid—wall models. Finally, a novel numerical algorithm combining two commercial codes for coupled solid/fluid problems is presented. As a consequence of the present studies, wall effects are now able to be included in predictions of haemodynamics in a clinical context.

scholarly journals Stratospheric Response to the 11-Yr Solar Cycle: Breaking Planetary Waves, Internal Reflection, and Resonance

2017 ◽  
Vol 30 (18) ◽  
pp. 7169-7190 ◽  
Author(s):  
Hua Lu ◽  
Lesley J. Gray ◽  
Ian P. White ◽  
Thomas J. Bracegirdle
Keyword(s):  
Wave Propagation ◽  
Solar Cycle ◽  
Wave Reflection ◽  
Surf Zone ◽  
Polar Vortex ◽  
High Latitudes ◽  
Solar Forcing ◽  
Reflected Waves ◽  
Wave Absorption ◽  
Pv Gradient

Abstract Breaking planetary waves (BPWs) affect stratospheric dynamics by reshaping the waveguides, causing internal wave reflection, and preconditioning sudden stratospheric warmings. This study examines observed changes in BPWs during the northern winter resulting from enhanced solar forcing and the consequent effect on the seasonal development of the polar vortex. During the period 1979–2014, solar-induced changes in BPWs were first observed in the uppermost stratosphere. High solar forcing was marked by sharpening of the potential vorticity (PV) gradient at 30°–45°N, enhanced wave absorption at high latitudes, and a reduced PV gradient between these regions. These anomalies instigated an equatorward shift of the upper-stratospheric waveguide and enhanced downward wave reflection at high latitudes. The equatorward refraction of reflected waves from the polar upper stratosphere then led to enhanced wave absorption at 35°–45°N and 7–20 hPa, indicative of a widening of the midstratospheric surf zone. The stratospheric waveguide was thus constricted at about 45°–60°N and 5–10 hPa in early boreal winter; reduced upward wave propagation through this region resulted in a stronger upper-stratospheric westerly jet. From January, the regions with enhanced BPWs acted as “barriers” for subsequent upward and equatorward wave propagation. As the waves were trapped within the stratosphere, anomalies of zonal wavenumbers 2 and 3 were reflected poleward from the stratospheric surf zone. Resonant excitation of some of these reflected waves resulted in rapid growth of wave disturbances and a more disturbed polar vortex in late winter. These results provide a process-oriented explanation for the observed solar cycle signal. They also highlight the importance of nonlinearity in the processes that drive the stratospheric response to external forcing.

scholarly journals 3D Numerical Simulation of Seamless Pipe Piercing Process by Fluid-Structure Interaction Method

2018 ◽  
Vol 203 ◽  
pp. 06016 ◽  
Author(s):  
Ameen Topa ◽  
Do Kyun Kim ◽  
Youngtae Kim
Keyword(s):  
Numerical Simulations ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Rolling Process ◽  
Arbitrary Lagrangian Eulerian ◽  
Analysis Method ◽  
Seamless Pipe ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Ale Formulation

Seamless pipes are produced using piercing rolling process in which round bars are fed between two rolls and pierced by stationary plug. During this process, the material undergoes severe deformation which renders it impractical to perform the numerical simulations with conventional finite element methods. In this paper, three dimensional numerical simulations of the piercing process are performed with Fluid-Structure Interaction (FSI) Method using Arbitrary Lagrangian-Eulerian (ALE) Formulation with LS DYNA software. The results of numerical simulations agree with experimental data of Plasticine workpiece and the validity of the analysis method is confirmed.

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