Experimental analysis of the effects of idealized surface groove amplitudes on post-stenotic pulsatile flow dynamics.

Surface irregularities can substantially modify local hemodynamics within coronary arteries. This study experimentally investigated the influence of controlled grooved surface geometries on pulsatile flow characteristics using idealized coronary-type stenosis models. Four transparent models were fabricated, consisting of a smooth control and three grooved surfaces with increasing groove amplitudes. Time-resolved particle image velocimetry was employed to quantify phase-averaged velocity fields, recirculation structures, and turbulent kinetic energy (TKE). The results showed that groove-induced surface irregularities enhanced jet deflection, near-wall recirculation, and in-plane cross-stream motion compared with the smooth stenosis model. As groove amplitude increased, downstream jet deflection became more pronounced, indicating a redistribution of velocity fluctuations in the post-stenotic region. In contrast, the smooth stenosis sustained a longer and more coherent jet structure. Increased groove amplitude also reduced the downstream extent and magnitude of measured planar TKE. These findings demonstrate that even small-scale surface features can significantly alter post-stenotic flow structures and the spatial development of turbulence under coronary-relevant pulsatile flow conditions.