Impact of Non-Newtonian Blood Analogues on Haemodynamics in a Compliant Carotid Bifurcation Phantom

In vitro modeling of cardiovascular hemodynamics is vital for understanding flow in complex arterial geometries. While computational studies increasingly use non-Newtonian blood models, they often lack validation, as experiments typically use Newtonian analogs for simplicity. Matching both fluid and optical properties for techniques like particle image velocimetry (PIV) is challenging. This study addresses these issues by comparing Newtonian and non-Newtonian analogs in a compliant carotid bifurcation phantom (35° angle) under physiologically realistic, pulsatile flow using Stereo PIV. The non-Newtonian analog mimics blood’s shear-thinning behavior via a power-law model; both analogs are dynamically scaled. Center-plane flow was measured at peak systole and end-diastole. Analysis includes velocity fields, profiles, shear-rate distributions, and wall displacement, all rescaled to in vivo conditions. Results show the non-Newtonian analog produces distinct velocity profiles, altering downstream flow topology. At peak systole, this leads to a larger separation region in the internal carotid artery, affecting the expected wall shear stress and cell residence time. This highlights the need for non-Newtonian modeling and proper scaling in hemodynamic studies. This work offers a new experimental approach with physiologically relevant results, which can also be used for CFD validation.