DEM-BEM coupling in time domain for one-dimensional wave propagation

2022 ◽  
Vol 135 ◽  
pp. 26-37
Author(s):  
Guilherme Barros ◽  
Andre Pereira ◽  
Jerzy Rojek ◽  
Klaus Thoeni
Keyword(s):  
Wave Propagation ◽  
Time Domain ◽  
One Dimensional ◽  
Dimensional Wave

A wave propagation model of blood flow in large vessels using an approximate velocity profile function

2007 ◽  
Vol 580 ◽  
pp. 145-168 ◽  
Author(s):  
DAVID BESSEMS ◽  
MARCEL RUTTEN ◽  
FRANS VAN DE VOSSE
Keyword(s):  
Wave Propagation ◽  
Time Domain ◽  
Three Dimensional ◽  
Local Pressure ◽  
Profile Function ◽  
Propagation Models ◽  
One Dimensional ◽  
Friction Term ◽  
The Time Domain ◽  
Dimensional Wave

Lumped-parameter models (zero-dimensional) and wave-propagation models (one-dimensional) for pressure and flow in large vessels, as well as fully three-dimensional fluid–structure interaction models for pressure and velocity, can contribute valuably to answering physiological and patho-physiological questions that arise in the diagnostics and treatment of cardiovascular diseases. Lumped-parameter models are of importance mainly for the modelling of the complete cardiovascular system but provide little detail on local pressure and flow wave phenomena. Fully three-dimensional fluid–structure interaction models consume a large amount of computer time and must be provided with suitable boundary conditions that are often not known. One-dimensional wave-propagation models in the frequency and time domain are well suited to obtaining clinically relevant information on local pressure and flow waves travelling through the arterial system. They can also be used to provide boundary conditions for fully three-dimensional models, provided that they are defined in, or transferred to, the time domain.Most of the one-dimensional wave propagation models in the time domain described in the literature assume velocity profiles and therefore frictional forces to be in phase with the flow, whereas from exact solutions in the frequency domain a phase difference between the flow and the wall shear stress is known to exist. In this study an approximate velocity profile function more suitable for one-dimensional wave propagation is introduced and evaluated. It will be shown that this profile function provides first-order approximations for the wall shear stress and the nonlinear term in the momentum equation, as a function of local flow and pressure gradient in the time domain. The convective term as well as the approximate friction term are compared to their counterparts obtained from Womersley profiles and show good agreement in the complete range of the Womersley parameter α. In the limiting cases, for Womersley parameters α → 0 and α → ∞, they completely coincide. It is shown that in one-dimensional wave propagation, the friction term based on the newly introduced approximate profile function is important when considering pressure and flow wave propagation in intermediate-sized vessels.

Longitudinal Collision of Rod-Rigid Element Systems

1983 ◽  
Vol 50 (3) ◽  
pp. 637-640 ◽  
Author(s):  
A. Mioduchowski ◽  
M. G. Faulkner ◽  
A. Pielorz ◽  
W. Nadolski
Keyword(s):  
Wave Propagation ◽  
Elastic Rods ◽  
Propagation Theory ◽  
One Dimensional ◽  
Rigid Element ◽  
Dimensional Wave

One-dimensional wave propagation theory is used to investigate the forces, velocities, and displacements in a series of elastic rods connected to rigid elements. The method is applied to the case of two subsystems that collide. The technique allows the calculations to be done during a short-lived event such as a collision.

Impact and One-Dimensional Wave Propagation

1997 ◽  
pp. 125-171
Author(s):  
H.R. Harrison ◽  
T. Nettleton
Keyword(s):  
Wave Propagation ◽  
One Dimensional ◽  
Dimensional Wave

Fracture of Lucite Cones by Shock Waves

1972 ◽  
Vol 39 (2) ◽  
pp. 390-394
Author(s):  
W. N. Sharpe
Keyword(s):  
Wave Propagation ◽  
Shock Waves ◽  
Tensile Stress ◽  
Fracture Criterion ◽  
Leading Edge ◽  
Propagation Theory ◽  
One Dimensional ◽  
Cone Axis ◽  
Cone Apex ◽  
Dimensional Wave

A compressive pulse applied to the base of a cone develops a tensile tail as it propagates toward the cone apex. This tension can cause fracture of the cone perpendicular to the cone axis before the leading edge of the pulse reaches the tip. It is shown that the elementary one-dimensional wave-propagation theory for cones and a time-independent critical tensile stress fracture criterion adequately describe the fracture of lucite cones subjected to narrow rectangular compressive pulses between 1 and 7 kilobars in magnitude.

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