Pulsatile Flow Through a Compliant Channel: A Comparison of Laminar and Fully Developed Turbulent Flow Effects

摘要

We investigate the fluid-structure interaction (FSI) of planePoiseuille and fully developed turbulent flows through a compliantchannel with flexible-plate-spring type walls. Althoughfundamental in nature, the study is partially motivated by itsapplication to the biomechanics of blood flow. Our main objectiveis to assess the effect of modulation frequency and channelcompliance on the wall shear stresses due to organized disturbancesduring the fundamental cycle of the unsteady meanflow. For the pulsatile plane Poiseuille mean flow an analyticalsolution is implemented, while the fully developed turbulentpulsatile mean flow is modelled via the unsteady RANS equationsusing the Boussinesq hypothesis for the Reynolds stresses.The eddy viscosity is calculated by solving the standard oneequationSpalart-Allmaras model. In order to compare the effectsof the two types of mean flow on the FSI, we use the samebulk Reynolds number, the same dimensional applied pressuregradientpulsation and the same dimensional properties for thecompliant walls at each of a low (Wo = 5) and high (Wo = 15)modulation frequency (where Wo is the Womersely number).Our results show that even though the wall shear stresses ofthe turbulent pulsatile mean flow are larger than those of thelaminar pulsatile mean flow within the pulsation cycle, the wallshear stresses induced by the organized disturbances are largerin the case of the laminar mean flow. Finally, wall compliance isshown to reduce the wall shear stresses due to the organized disturbancesin all cases but this effect is more pronounced for thelaminar mean flow at the low modulation frequency (Wo = 5).