Fluid-structure interaction of steady and pulsating flow through a collapsible thin-walled vessel

Abstract

An experimental study has been conducted to investigate complex fluid-structure interactions in collapsible tubes under steady and pulsatile flow conditions, which holds significant implications for many physiological fluid transport phenomena. Quantitative analysis of structural deformation and flow field analysis were conducted utilizing Particle Image Velocimetry (PIV) and optical image analysis. The results suggest that the tube wall deformation followed Shapiro’s tube law under static and low-Re steady flow conditions. An increase in flow magnitude triggered self-excited oscillation under a critical range of negative transmural pressure. PIV results revealed periodic asymmetric jet downstream alongside velocity fluctuations during self-excited oscillation. Pulsatile flow induced cyclic symmetrical buckling under positive and neutral transmural pressures, while created traveling wave patterns under negative transmural pressures. Under highly negative transmural pressures, tube collapsed during diastole, limiting the mean flow rate. Brief self-excited oscillation was observed under such conditions, amplifying the peak flow rate within a pulsatile cycle.