Laminar, Turbulent, and Transitional Simulations in Benchmark Cases with Cardiovascular Device Features

Bhushan, Shanti; Walters, D. Keith; Burgreen, Greg W.

doi:10.1007/s13239-013-0155-5

Cited by 26 publications

(23 citation statements)

References 34 publications

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“…The reported computational investigations on this FDA benchmark can be divided into two major groups: blinded studies that were conducted without foreknowledge of the experimental results and the studies conducted after the publication of first benchmark results. While none of the first 28 CFD research groups which used various RANS methods managed to fully reproduce the FDA experimental results [24], almost all succeeding CFD studies [27][28][29][30] reported good agreement with the FDA experiments. This raises a number of questions regarding both the numerical Fig.…”

Section: The Fda Medical Device Test Casementioning

confidence: 99%

Large-Eddy Simulation of Turbulence in Cardiovascular Flows

Nicoud¹,

Chnafa

Sigüenza³

et al. 2017

Lecture Notes in Applied and Computational Mechanics

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A 4th-order accurate, low dissipative flow solver is used to perform Large-Eddy Simulations of three typical hemodynamic situations: the flow through the idealized medical device proposed by the American Food and Drug Administration; the intracardiac flow within an actual human left heart whose morphology and deformations are deduced from medical imaging; the flow downstream of an artificial aortic valve which arises from the blood-leaflets interaction problem. In all the cases, the subgrid scale model designed to handle wall-bounded transitional flows is successfully used and the numerical simulations compare favourably with the experimental data available. These results illustrate the potential of the Large-Eddy Simulation methodology to properly handle blood flows. They also support the idea that turbulence, even if not fully developed, may be present in cardiovascular flows, including under non pathological conditions.

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Section: The Fda Medical Device Test Casementioning

confidence: 99%

Large-Eddy Simulation of Turbulence in Cardiovascular Flows

Nicoud¹,

Chnafa

Sigüenza³

et al. 2017

Lecture Notes in Applied and Computational Mechanics

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“…Solution strategies include direct numerical simulation, 12 large eddy simulation (LES), [13][14][15] or a dynamic hybrid Reynolds-averaged Navier-Stokes (RANS)/LES model. 46 The fact that RANS 47 and LES 48 models are generally too dissipative, and not suitable to studying flows in the transitional regime, is beyond the point; all studies where the authors were nonblinded to the in vitro results showed reasonable agreement with the measurements.…”

Section: Figurementioning

confidence: 99%

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

Bergersen

Mortensen

Valen‐Sendstad

2018

Numer Methods Biomed Eng

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The utility of flow simulations relies on the robustness of computational fluid dynamics (CFD) solvers and reproducibility of results. The aim of this study was to validate the Oasis CFD solver against in vitro experimental measurements of jet breakdown location from the FDA nozzle benchmark at Reynolds number 3500, which is in the particularly challenging transitional regime. Simulations were performed on meshes consisting of 5, 10, 17, and 28 million (M) tetrahedra, with Δt = 10 seconds. The 5M and 10M simulation jets broke down in reasonable agreement with the experiments. However, the 17M and 28M simulation jets broke down further downstream. But which of our simulations are "correct"? From a theoretical point of view, they are all wrong because the jet should not break down in the absence of disturbances. The geometry is axisymmetric with no geometrical features that can generate angular velocities. A stable flow was supported by linear stability analysis. From a physical point of view, a finite amount of "noise" will always be present in experiments, which lowers transition point. To replicate noise numerically, we prescribed minor random angular velocities (approximately 0.31%), much smaller than the reported flow asymmetry (approximately 3%) and model accuracy (approximately 1%), at the inlet of the 17M simulation, which shifted the jet breakdown location closer to the measurements. Hence, the high-resolution simulations and "noise" experiment can potentially explain discrepancies in transition between sometimes "sterile" CFD and inherently noisy "ground truth" experiments. Thus, we have shown that numerical simulations can agree with experiments, but for the wrong reasons.

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“…Reportedly, velocity statistical data using the Smagorinsky model in Fluent were in very good agreement in the sudden expansion region and slightly underpredicted in the throat. uRANS and HRL methods reported in [13] yielded a variable performance. While the Fluent detached eddy simulations failed to correctly predict the Re th D 3500 case, SST uRANS overpredicted turbulence levels in the same case.…”

Section: Introductionmentioning

confidence: 99%

About the numerical robustness of biomedical benchmark cases: Interlaboratory FDA's idealized medical device

Zmijanović

Mendez

Moureau

et al. 2016

Numer Methods Biomed Eng

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The need for reliable approaches in numerical simulations stands out as a critical issue for the development and optimization of cardiovascular biomedical devices. This led the US Food and Drug Administration to undertake a programme of validation of computational fluid dynamics methods for transitional and turbulent flows. In the current investigation, large-eddy simulation is used to simulate the flow in the first benchmark medical device, and results are confronted to the existing laboratory experiments. This idealized medical device has the particularity to feature transition to turbulence after a sudden expansion. The effects of numerical parameters and low-level inlet perturbations are investigated. Results indicate a considerable impact of numerical aspects on the prediction of the location of the transition to turbulence. The study also demonstrates that injecting small perturbations at the inflow greatly improves the streamwise velocity estimation in the transition region and substantially contributes to the robustness of the flow statistical data. Copyright © 2016 John Wiley & Sons, Ltd.

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Laminar, Turbulent, and Transitional Simulations in Benchmark Cases with Cardiovascular Device Features

Cited by 26 publications

References 34 publications

Large-Eddy Simulation of Turbulence in Cardiovascular Flows

Large-Eddy Simulation of Turbulence in Cardiovascular Flows

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

About the numerical robustness of biomedical benchmark cases: Interlaboratory FDA's idealized medical device

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