Fluid friction and wall viscosity of the 1D blood flow model

TL;DR

This study models blood pulse waves in a flexible tube, estimating fluid friction and wall viscosity coefficients by fitting a nonlinear 1D flow model to experimental data, highlighting the importance of wall viscosity.

Contribution

It introduces a method to separately estimate fluid friction and wall viscosity coefficients in a 1D blood flow model using experimental data.

Findings

Wall viscosity significantly affects pulse wave damping.

The model accurately predicts experimental pressure and displacement data.

Wall viscosity's impact is comparable to fluid viscosity in pulse wave attenuation.

Abstract

We study the behavior of the pulse waves of water into a flexible tube for application to blood flow simulations. In pulse waves both fluid friction and wall viscosity are damping factors, and difficult to evaluate separately. In this paper, the coefficients of fluid friction and wall viscosity are estimated by fitting a nonlinear 1D flow model to experimental data. In the experimental setup, a distensible tube is connected to a piston pump at one end and closed at another end. The pressure and wall displacements are measured simultaneously. A good agreement between model predictions and experiments was achieved. For amplitude decrease, the effect of wall viscosity on the pulse wave has been shown as important as that of fluid viscosity.