Modeling of an Intravascular Stent Using the Navier Boundary Condition with Variable Slip Length: 2D Analysis of Hemodynamic Characteristics

This paper presents a new approach to modeling an intravascular stent in a two-dimensional problem formulation. This approach uses a variable-slip Navier boundary condition, simulating the periodic structure of the stent (wire thickness and number of turns). Unlike explicit modeling of stent geometry or a porous-medium approach, the proposed method reduces computational costs and takes into account major geometric parameters. The steady-state flow of a viscous incompressible fluid in a flat channel is supplemented by an analytical description of planar Hill vortex analogs in sinusoidal valleys. Numerical experiments in ANSYS are used to study the influence of wire thickness (120–400 μm) and the number of peaks (10, 30, 50) on the change in flow velocity, wall shear stress (WSS), and the specific dissipation function. It was found that increasing the wire thickness leads to an increase in velocity (up to 24%) and a decrease in WSS (up to 13%), with a weak dependence on the number of peaks in steady-state mode. In quasi-steady (pulsating) flow, the influence of stent periodicity becomes more pronounced. The value of the dissipative function decreases with increasing wire thickness (up to 25%), indicating a reduction in viscous losses due to sliding. The proposed method may be useful for rapid screening assessment of the hemodynamic effects of stents during the preclinical design stage.