Inertia effects and stress accumulation in a constricted duct: A combined experimental and lattice Boltzmann study

TL;DR

This study combines experimental and lattice Boltzmann simulations to analyze how inertia effects influence shear stress in constricted blood vessels, revealing non-linear stress growth at higher Reynolds numbers that could impact clotting risk.

Contribution

It provides new insights into non-linear shear stress behavior in constricted flows using combined experimental and numerical approaches, especially relevant for blood flow analysis.

Findings

Shear stress peaks grow disproportionately with Reynolds number.

Non-linear shear stress accumulation occurs at Re > 10.

Higher Reynolds numbers in constricted vessels may elevate clotting risk.

Abstract

We experimentally and numerically investigate the flow of a Newtonian fluid through a constricted geometry for Reynolds numbers in the range $0.1 - 100$. The major aim is to study non-linear inertia effects at larger Reynolds numbers (>10) on the shear stress evolution in the fluid. This is of particular importance for blood flow as some biophysical processes in blood are sensitive to shear stresses, e.g., the initialization of blood clotting. We employ the lattice Boltzmann method for the simulations. The conclusion of the predictions is that the peak value of shear stress in the constriction grows disproportionally fast with the Reynolds number which leads to a non-linear shear stress accumulation. As a consequence, the combination of constricted blood vessel geometries and large Reynolds numbers may increase the risk of undesired blood clotting.