Influence of Shear-Thinning Blood Rheology on the Laminar-Turbulent Transition over a Backward Facing Step

摘要: Cardiovascular diseases are the leading cause of death globally and there is an unmet need for effective, safer blood-contacting devices, including valves, stents artificial hearts. In these, recirculation regions promote thrombosis, triggering mechanical failure, neurological dysfunction infarctions. Transitional flow over a backward facing step idealised model these conditions; aim was to understand impact non-Newtonian blood rheology on modelling this flow. Flow simulations shear-thinning Newtonian fluids were compared Reynolds numbers ( R e ) covering comprehensive range laminar, transitional turbulent first time. Both unsteady Averaged Navier–Stokes k − ω SST) Smagorinsky Large Eddy Simulations (LES) assessed; only LES correctly predicted trends in zone length all . Turbulent-transition assessed by several criteria, revealing complex picture. Instantaneous parameters, such as velocity, indicated delayed transition: = 1600 versus 2000, transitions, respectively. Conversely, when using Re defined spatially averaged viscosity, transitioned below Newtonian. However, length, mean parameter, did not indicate any difference between two. This work shows can explain transition whole seen published experimental data, but delay full story. The results show that, accurately flow, so enable design advanced cardiovascular it essential incorporate rheology, explicitly eddies.