scholarly journals Propagation of Nonlinear Pressure Waves in Blood

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
A. Elgarayhi ◽  
E. K. El-Shewy ◽  
Abeer A. Mahmoud ◽  
Ali A. Elhakem
Keyword(s):  
Vries Equation ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Elastic Tube ◽  
Pressure Waves ◽  
Weakly Nonlinear ◽  
Flow Problems ◽  
Inner Radius ◽  
Reductive Perturbation ◽  
Conditions Of Stability

The propagation of weakly nonlinear pressure waves in a fluid-filled elastic tube has been investigated. The reductive perturbation method has been employed to derive the Korteweg-de Vries equation for small but finite amplitude. The effect of the final inner radius of the tube on the basic properties of the soliton wave was discussed. Moreover, the conditions of stability and the soliton existence via the potential and the corresponding phase portrait were computed. The applicability of the present investigation to flow problems in arteries is discussed.

Solitary waves in a dusty adiabatic electronegative plasma

2010 ◽  
Vol 76 (3-4) ◽  
pp. 409-418 ◽  
Author(s):  
A. A. MAMUN ◽  
K. S. ASHRAFI ◽  
M. G. M. ANOWAR
Keyword(s):  
Solitary Waves ◽  
Vries Equation ◽  
Negative Ions ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Charged Dust ◽  
Electronegative Plasma ◽  
Ion Acoustic ◽  
Basic Features ◽  
Electronegative Plasmas

AbstractThe dust ion-acoustic solitary waves (SWs) in an unmagnetized dusty adiabatic electronegative plasma containing inertialess adiabatic electrons, inertial single charged adiabatic positive and negative ions, and stationary arbitrarily (positively and negatively) charged dust have been theoretically studied. The reductive perturbation method has been employed to derive the Korteweg-de Vries equation which admits an SW solution. The combined effects of the adiabaticity of plasma particles, inertia of positive or negative ions, and presence of positively or negatively charged dust, which are found to significantly modify the basic features of small but finite-amplitude dust-ion-acoustic SWs, are explicitly examined. The implications of our results in space and laboratory dusty electronegative plasmas are briefly discussed.

PROPAGATION OF WEAKLY NONLINEAR WAVES IN A FLUID-FILLED THIN ELASTIC TUBE

1999 ◽  
Vol 23 (2) ◽  
pp. 253-265
Author(s):  
H. Demiray
Keyword(s):  
Nonlinear Waves ◽  
Vries Equation ◽  
Perturbation Technique ◽  
Fluid Pressure ◽  
Static Field ◽  
Elastic Tube ◽  
Inviscid Fluid ◽  
Weakly Nonlinear ◽  
De Vries ◽  
Weakly Nonlinear Waves

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.

Localized coherent nonlinear wave structures in dusty plasma with non-thermal ions

2007 ◽  
Vol 73 (6) ◽  
pp. 921-932 ◽  
Author(s):  
TARSEM SINGH GILL ◽  
CHANCHAL BEDI ◽  
NARESHPAL SINGH SAINI ◽  
HARVINDER KAUR
Keyword(s):  
Perturbation Method ◽  
Solitary Waves ◽  
Vries Equation ◽  
Thermal Parameter ◽  
Reductive Perturbation Method ◽  
Double Layers ◽  
Dust Charge ◽  
Dust Acoustic Solitary Waves ◽  
Reductive Perturbation ◽  
Dust Acoustic

AbstractIn the present research paper, the characteristics of dust-acoustic solitary waves (DASWs) and double layers (DLs) are studied. Ions are treated as non-thermal and variable dust charge is considered. The Korteweg–de Vries equation is derived using a reductive perturbation method. It is noticed that compressive solitons are obtained up to a certain range of relative density δ (=ni0/ne0) beyond which rarefactive solitons are observed. The study is further extended to investigate the possibility of DLs. Only compressive DLs are permissible. Both DASWs and DLs are sensitive to variation of the non-thermal parameter.

Solitons, solitary waves, and voidage disturbances in gas-fluidized beds

1994 ◽  
Vol 266 ◽  
pp. 243-276 ◽  
Author(s):  
S. E. Harris ◽  
D. G. Crighton
Keyword(s):  
Vries Equation ◽  
Solitary Wave Solution ◽  
Finite Amplitude ◽  
Order Equation ◽  
Leading Order ◽  
Dimensional Model ◽  
Weakly Nonlinear ◽  
One Dimensional ◽  
Weakly Nonlinear Waves ◽  
Gas Fluidized Beds

In this paper, we consider the evolution of an initially small voidage disturbance in a gas-fluidized bed. Using a one-dimensional model proposed by Needham & Merkin (1983), Crighton (1991) has shown that weakly nonlinear waves of voidage propagate according to the Korteweg–de Vries equation with perturbation terms which can be either amplifying or dissipative, depending on the sign of a coefficient. Here, we investigate the unstable side of the threshold and examine the growth of a single KdV voidage soliton, following its development through several different regimes. As the size of the soliton increases, KdV remains the leading-order equation for some time, but the perturbation terms change, thereby altering the dependence of the amplitude on time. Eventually the disturbance attains a finite amplitude and corresponds to a fully nonlinear solitary wave solution. This matches back directly onto the KdV soliton and tends exponentially to a limiting size. We interpret the series of large-amplitude localized pulses of voidage formed in this way from initial disturbances as corresponding to the ‘voidage slugs’ observed in gas fluidization in narrow tubes.

Amplification and decay of long nonlinear waves

1973 ◽  
Vol 58 (3) ◽  
pp. 481-493 ◽  
Author(s):  
S. Leibovich ◽  
J. D. Randall
Keyword(s):  
Shallow Water ◽  
Nonlinear Waves ◽  
Water Waves ◽  
Vries Equation ◽  
Variable Coefficients ◽  
Finite Amplitude ◽  
Rotating Fluids ◽  
Shallow Water Waves ◽  
Weakly Nonlinear ◽  
Weakly Nonlinear Waves

The interaction of weakly nonlinear waves with slowly varying boundaries is considered. Special emphasis is given to rotating fluids, but the analysis applies with minor modifications to waves in stratified fluids and shallow-water aves. An asymptotic solution of a variant of the Korteweg–de Vries equation with variable coefficients is developed that produces a ‘Green's law’ for the amplification of waves of finite amplitude. For shallow-water waves in water of variable depth, the result predicts wave growth proportional to the $-\frac{1}{3}$ power of the depth.

The Effects of Higher-Order Approximations in a Fluid-Filled Elastic Tube with Stenosis

2006 ◽  
Vol 61 (12) ◽  
pp. 641-651
Author(s):  
Hilmi Demiray
Keyword(s):  
Evolution Equation ◽  
Wave Speed ◽  
Kdv Equation ◽  
Order Term ◽  
Perturbation Expansion ◽  
Reductive Perturbation Method ◽  
Elastic Tube ◽  
Inviscid Fluid ◽  
Weakly Nonlinear ◽  
Elastic Tubes

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.

Nonlinear magnetoacoustic waves in pair-ion plasma with dust impurity

2013 ◽  
Vol 79 (5) ◽  
pp. 825-831 ◽  
Author(s):  
SHI-SEN RUAN ◽  
JIANG-HONG MAN ◽  
SHAN WU ◽  
ZE CHENG
Keyword(s):  
Magnetic Field Intensity ◽  
Vries Equation ◽  
Reductive Perturbation Method ◽  
Dust Particles ◽  
Number Density ◽  
Nonlinear Properties ◽  
Variation Of Parameters ◽  
Ion Plasma ◽  
Magnetoacoustic Waves ◽  
Reductive Perturbation

AbstractNonlinear properties of magnetoacoustic waves are investigated in magnetized pair-ion plasmas with dust impurity. Three-fluid collisionless magneto-hydrodynamic model is considered and reductive perturbation method is employed to derive Korteweg-de Vries equation for magnetoacoustic solitary waves (MASWs). The effects of the charge number of dust particles, magnetic field intensity, and plasma number density are studied on MASWs. It is found that the variation of parameters causes significant changes in solitary structures. The present investigation may be useful to understand formation and propagation of MASW structures in dust pair-ion plasmas.

Shock wave occurrence and soliton propagation in polariton condensates

2017 ◽  
Vol 95 (12) ◽  
pp. 1234-1238 ◽  
Author(s):  
A.M. Belounis ◽  
S. Kessal
Keyword(s):  
Shock Wave ◽  
Burgers Equation ◽  
Vries Equation ◽  
Reductive Perturbation Method ◽  
Pitaevskii Equation ◽  
Soliton Propagation ◽  
Modified Burgers Equation ◽  
Reductive Perturbation ◽  
De Vries ◽  
Dispersionless Limit

We study the effects of the gain and the loss of polaritons on the wave propagation in polariton condensates. This system is described by a modified Gross–Pitaevskii equation. In the case of small damping, we use the reductive perturbation method to transform this equation; we get a modified Burgers equation in the dispersionless limit and a damped Korteweg – de Vries equation in a more general case. We demonstrate that the shock wave occurrence depends on the gain and the loss of polaritons in the dispersionless polariton condensate. The resolution of the damped Korteweg – de Vries equation shows that the soliton behaves like a damped wave in the case of a constant damping. Based on an asymptotic solution, the survival time and the distance traveled by this soliton are evaluated. We solve the damped Korteweg – de Vries equation and the modified Gross–Pitaevskii numerically to validate the analytical calculations and discuss especially the soliton propagation in the system.

scholarly journals Modulation of nonlinear waves in a fluid-filled elastic tube with stenosis

2004 ◽  
Vol 2004 (60) ◽  
pp. 3205-3218 ◽  
Author(s):  
Hilmi Demiray
Keyword(s):  
Evolution Equation ◽  
Amplitude Modulation ◽  
Nonlinear Waves ◽  
Variable Coefficient ◽  
Composite System ◽  
Harmonic Wave ◽  
Reductive Perturbation Method ◽  
Elastic Tube ◽  
Reductive Perturbation ◽  
Thin Walled

Treating the arteries as a thin-walled and prestressed elastic tube with a stenosis and the blood as a Newtonian fluid with negligible viscosity, we have studied the amplitude modulation of nonlinear waves in such a composite system by use of the reductive perturbation method. The governing evolution equation is obtained as the variable-coefficient nonlinear Schrödinger equation. It is observed that the speed of the harmonic wave increases with distance from the center of stenosis.

Nonlinear magnetoacoustic waves in a weakly inhomogeneous plasma

1980 ◽  
Vol 58 (1) ◽  
pp. 110-115
Author(s):  
D. Govinda Thirtha ◽  
M. L. Mittal
Keyword(s):  
Magnetic Field ◽  
Solitary Wave ◽  
Wave Amplitude ◽  
Vries Equation ◽  
Inhomogeneous Plasma ◽  
State Density ◽  
Reductive Perturbation Method ◽  
The Other ◽  
Magnetoacoustic Waves ◽  
Reductive Perturbation

Nonlinear magnetoacoustic waves in a weakly inhomogeneous plasma are analysed by reductive perturbation method. One-dimensionai spatial variations are considered in the equilibrium state (density, temperature, and magnetic field) of the system. The governing equation turns out to be a modified Korteweg – de Vries equation which includes damping effects. It is found that the combined effect of the temperature and magnetic field inhomogeneities on the solitary wave amplitude is such that each inhomogeneity counterinfluences the other.

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