Non-symmetrical waves in a prestressed elastic tube filled with an inviscid fluid

1994 ◽  
Vol 32 (4) ◽  
pp. 605-616 ◽  
Author(s):  
Hilmi Demiray ◽  
Ali Ercengiz
Keyword(s):  
2007 ◽  
Vol 62 (1-2) ◽  
pp. 21-28
Author(s):  
Hilmi Demiray

In this work, treating an artery as a prestressed thin-walled elastic tube and the blood as an inviscid fluid, the interactions of two nonlinear waves propagating in opposite directions are studied in the longwave approximation by use of the extended PLK (Poincaré-Lighthill-Kuo) perturbation method. The results show that up to O(k3), where k is the wave number, the head-on collision of two solitary waves is elastic and the solitary waves preserve their original properties after the interaction. The leading-order analytical phase shifts and the trajectories of two solitons after the collision are derived explicitly.


1999 ◽  
Vol 23 (2) ◽  
pp. 253-265
Author(s):  
H. Demiray

In this work, we study the propagation of weakly nonlinear waves in a prestressed thin elastic tube filled with an inviscid fluid. In the analysis, considering the physiological conditions under which the arteries function, the tube is assumed to be subjected to a uniform pressure P0 and a constant axial stretch ratio λz. In the course of blood flow in arteries, it is assumed that a finite time dependent radial displacement is superimposed on this static field but, due to axial tethering, the effect of axial displacement is neglected. The governing nonlinear equation for the radial motion of the tube under the effect of fluid pressure is obtained. Using the exact nonlinear equations of an incompressible inviscid fluid and the reductive perturbation technique, the propagation of weakly nonlinear waves in a fluid-filled thin elastic tube is investigated in the longwave approximation. The governing equation for this special case is obtained as the Korteweg-de-Vries equation. It is shown that, contrary to the result of previous works on the same subject, in the present work, even for Mooney-Rivlin material, it is possible to obtain the nonlinear Korteweg-de-Vries equation.


2018 ◽  
Author(s):  
Nur Fara Adila Binti Ahmad ◽  
Choy Yaan Yee ◽  
Tay Kim Gaik

2006 ◽  
Vol 61 (12) ◽  
pp. 641-651
Author(s):  
Hilmi Demiray

Treating arteries as thin-walled prestressed elastic tubes with a narrowing (stenosis) and blood as an inviscid fluid, we study the propagation of weakly nonlinear waves in such a fluid-filled elastic tube by employing the reductive perturbation method in the long wave approximation. It is shown that the evolution equation of the first-order term in the perturbation expansion may be described by the conventional Korteweg-de Vries (KdV) equation. The evolution equation for the second-order term is found to be the linearized KdV equation with a nonhomogeneous term, which contains the contribution of the stenosis. A progressive wave type solution is sought for the evolution equation, and it is observed that the wave speed is variable, which results from the stenosis. We study the variation of the wave speed with the distance parameter τ for various amplitude values of the stenosis. It is observed that near the center of the stenosis the wave speed decreases with increasing stenosis amplitude. However, sufficiently far from the center of the stenosis stenosis amplitude becomes negligibly small.


Author(s):  
Hilmi Demiray ◽  
Sadik Dost

This article presents a theoretical analysis for the wave propagation in a thin walled prestressed elastic tube filled with an inviscid fluid. Considering the blood flow in human artery and its physiological conditions, the tube is assumed to be initially subjected to a mean pressure Pi and the axial stretch λ2. The governing equations of the tube and the fluid are obtained by adding a small incremental disturbance on this initial field. In the formulation, the interaction between the blood and its container is taken into account. A harmonic wave type of solution is sought for the field equations, and the associated dispersion relation is obtained by using appropriate boundary conditions. Some special cases as well as a general case are thoroughly discussed and the results of the present formulation is compared with those of the relevant literature.


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