Arterial Stent: Pulsatile Blood Flow, UDF

Arterial Stent CFD Simulation, Improving Blood Flow and Reducing Shear Stress, ANSYS Fluent

Description

This project simulates blood flow through arteries both with and without a stent present, using ANSYS Fluent, investigating how stent implantation affects hemodynamics — particularly shear stress and pressure distribution, both of which play critical roles in cardiovascular health.

Two geometries were built in SpaceClaim: the first representing a stenotic artery without a stent, using a defined equation to construct the clogged (narrowed) region, and the second representing the same artery with a stent implanted. The stenotic artery mesh totaled over 220,000 cells, while the stented artery mesh totaled approximately 250,000 cells, both generated in ANSYS Meshing.

Methodology

The simulation used a pressure-based solver with a transient formulation to capture the time-dependent nature of blood flow, with the Eulerian multiphase model enabled to distinguish between the blood and arterial wall interfaces.

Pulsatile blood flow was applied at the inlet through a custom UDF, with velocity ranging from 0 to 0.33 m/s to mimic realistic arterial flow conditions, with outlet velocity profiles monitored throughout the simulation. The Coupled algorithm handled pressure-velocity coupling, with the PRESTO! scheme used for pressure calculations. Simulations were initialized using standard methods, run with a time step of 0.001 seconds over a total of 200 time steps.

Conclusion

The results reveal clear differences between the two cases across several key metrics. Shear stress distribution differed substantially: the stenotic artery without a stent exhibited high shear stress regions — conditions that can potentially damage endothelial cells and raise thrombosis risk — while the stented case showed a marked reduction in shear stress, indicating improved hemodynamics and reduced complication risk.

Pressure distribution also varied meaningfully, with the stenotic artery showing higher overall pressure than the stented case — consistent with expectations, since the stent alleviates the arterial narrowing and facilitates smoother blood flow, easing the pressure burden.

Outlet velocity profiles further supported this trend: the stented artery displayed a more uniform, consistent velocity pattern over time, reflecting improved flow characteristics compared to the unstented stenotic case.

Together, these results demonstrate the clear hemodynamic benefits of arterial stent implantation — lower shear stress, more favorable pressure distribution, and more stable outlet flow — underscoring both the clinical value of stenting in managing cardiovascular disease and the usefulness of computational simulation for evaluating and optimizing such medical interventions.