Vibro-acoustic radiation from a fluid-filled viscoelastic cylindrical shell with internal turbulent flow

The vibration of a thin-walled cylindrical, compliant viscoelastic tube with internal flow and an axisymmetric constriction that results in turbulent fluid flow is studied theoretically and experimentally. Vibration of the tube is considered with internal fluid-coupling only and with coupling to internal flowing fluid and external stagnant fluid or external tissue-like viscoelastic material. The theoretical analysis includes the adaptation of a model for turbulence in the internal fluid and its vibratory excitation of and interaction with the tube wall and surrounding viscoelastic medium. Theoretical predictions are compared with experimental measurements conducted on a flow model system using laser Doppler vibrometry to measure tube vibration and the vibration of the surrounding viscoelastic medium, as well as miniature hydrophones to measure fluid pressure in the tube. Discrepencies between theory and experiment and the coupled nature of the fluid-structure interaction are highlighted. This study is relevant to and may provide further incite into vascular patency and mechanisms of failure, as well as diagnostics via noninvasive acoustic measurements.