Large Eddy Simulation of FDA’s Idealized Medical Device

Abstract

A hybrid large eddy simulation (LES) and immersed boundary method (IBM) computational approach is used to make quantitative predictions of flow field statistics within the Food and Drug Administration’s (FDA) idealized medical device. An in-house code is used, hereafter (W enoHemo™), that combines high-order finite-difference schemes on structured staggered Cartesian grids with an IBM to facilitate flow over or through complex stationary or rotating geometries and employs a subgrid-scale (SGS) turbulence model that more naturally handles transitional flows [2]. Predictions of velocity and wall shear stress statistics are compared with previously published experimental measurements from Hariharan et al. [6] for the four Reynolds numbers considered.

The FDA nozzle benchmark: “In theory there is no difference between theory and practice, but in practice there is”

“…Delorme et al performed a refinement study for R e = 2000, where the most resolved mesh had the equivalent to approximately 42M linear elements. Although the mesh resolution does not differ much from ours, the results still do.…”

“…Interestingly, none of the CFD benchmark participants obtained results in agreement with the in vitro measurements for Reynolds numer (Re) 3500, although good agreement and excellent CFD results have been reported by multiple authors retrospectively. [12][13][14][15] The FDA nozzle benchmark model remains highly relevant for biomedical problems and our aim was to further validate the open-source CFD solver Oasis 16 that we have extensively used to study turbulent-like cardiovascular flows. [17][18][19][20][21][22][23] We focus on the flow at Re = 3500, which is in the particularly challenging transitional flow regime, for which the in vitro experiments displayed the least variability.…”

Multiblock high order Large Eddy Simulation of powered Fontan hemodynamics: Towards computational surgery

“…This model is easy to implement, efficient to use, and applicable to fully inhomogeneous turbulent flows[3, 13, 14, 49]. This model gives: $${\nu }_T=C{\mathrm{normal\Pi }}^g$$ $${\mathrm{normal\Pi }}^g=\sqrt{\frac{B_{\beta }}{{\alpha }_{ij}{\alpha }_{ij}}}$$ with…”

“…The diffusion terms and the sub-grid stress tensor arising from the filtering of the equations are computed using fourth order accurate centered difference schemes. The implementation of the methods were tested and validated in our previous studies[3, 13, 14]. …”

Large Eddy Simulation of Transitional Flow in an Idealized Stenotic Blood Vessel: Evaluation of Subgrid Scale Models

“…Further details about the mirroring IBM can be found in Mark and Vanwachem [21], and the specific implementation used in the present solver can be found in Delorme et al [27]. Application of the present solver to validate the recent food and drug administration's critical path project is carried out in Delorme et al [28].…”