Experimental analysis of the fluid–structure interaction in finite-length straight elastic vessels

Numerous bio-mechanical flow problems are characterized by fluid–structure interaction phenomena. To analyze in detail the impact of fluid–structure interaction on the overall flow structure and the wall motion the oscillating laminar flow in an elastic vessel is experimentally investigated by time-resolved particle image velocimetry and pressure measurements. The vessel deformation amplitude is varied between 0.5% and 6% of the vessel diameter at Reynolds number and Womersley number ranges of 300≤Re≤1000 and 5≤Wo≤10. Motivated by Womersley’s fundamental results for rigid and elastic vessels it is the purpose of this study to extend the discussion to vessels of finite length undergoing high dilatation amplitudes and to provide benchmark data for numerical fluid–structure interaction methods. A detailed discussion of the results of the volume flux distribution, static pressure distribution, rate of change of the diameter, and wall-shear stress distribution is given and evidences a significant effect of vessel deformation on the distribution of the flow quantities. The inlet volume flux distribution excited by the piston pump generates an internal pressure distribution determining the vessel deformation which via the temporal derivative of the diameter change generates a delayed volume flux distribution that is superimposed onto the inlet volume flux. The comparison of the results with comparable rigid pipe flows shows variations in the velocity profile amplitude of up to 10% depending on the phase angle. The vessel elasticity leads to a wall-shear stress reduction during forward flow of up to 20%.