Impact of Turbulence Modeling on the Simulation of Blood Flow in Aortic Coarctation

TL;DR

This study evaluates how different turbulence models affect blood flow simulation accuracy in aortic coarctation, highlighting the importance of model choice and finite element order on clinical biomarker estimation.

Contribution

It compares multiple LES and variational multiscale turbulence models within a finite element framework for blood flow simulation in aortic coarctation, revealing their impact on clinical biomarker accuracy.

Findings

Most turbulence models agree on severity indicators like pressure difference.

Second order velocity elements improve accuracy over first order elements.

Different turbulence models can significantly affect wall shear stress estimates.

Abstract

Numerical simulations of pulsatile blood flow in an aortic coarctation require the use of turbulence modeling. This paper considers three models from the class of large eddy simulation (LES) models (Smagorinsky, Vreman, $\boldsymbol{\sigma}$-model) and one model from the class of variational multiscale models (residual-based) within a finite element framework. The influence of these models on the estimation of clinically relevant biomarkers used to assess the degree of severity of the pathological condition (pressure difference, secondary flow degree, normalized flow displacement, wall shear stress) is investigated in detail. The simulations show that most methods are consistent in terms of severity indicators such as pressure difference and stenotic velocity. The numerical results indicate that second order velocity elements outperform first order elements in terms of accuracy. Moreover, using second order velocity finite elements, different turbulence models might lead to considerably different results concerning other clinically relevant quantities such as wall shear stresses. These differences may be attributed to differences in numerical dissipation introduced by the turbulence models.