Wave reflection and transmission in multiply stented blood vessels

The Herschel-Quincke tube with modulated branches

The Herschel-Quincke (HQ) tube concept for transmission loss in pipe systems is expanded to include cases of branches with modulated properties. Modulated waveguides, featuring corrugations in their geometry or speed of sound, are known to produce significant reflection even without the parallel branch of the HQ tube. The HQ tube, in its classical form, produces narrow banded transmission loss at frequencies related to the length, wavenumber and cross-section area of the parallel branch. The modulated Herschel-Quincke (MHQ) tube combines these attributes to produce enhanced transmission loss characteristics in terms of both width and number of transmission loss bands. Several modulated profiles for the speed of sound in different branches of the tube are considered and analytical expressions for the transmission loss and resonant conditions are derived. Detailed analysis of periodically stratified branch profiles demonstrates the effectiveness of the MHQ tube for fluid-borne noise attenuation in pipe systems. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 2)'.

Dispersion of waves and transmission-reflection in blood vessels with structured stents

A new model is proposed for elastic waves induced by a pulsating flow in a stenotic artery containing several stents. Dispersion properties of the waves depend on the stent structure-this feature is addressed in the present paper. Several vascular stenting procedures include overlapping stents; this configuration is also included in the model. The dispersion and transmission properties are analysed; the analytical derivations are accompanied by illustrative numerical examples.

Waves and fluid-solid interaction in stented blood vessels

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.