Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser

Sandy F.C. Stewart, Prasanna Hariharan, Eric G. Paterson, Greg W. Burgreen, Varun Reddy, Steven W. Day, Matthew Giarra, Keefe B. Manning, Steven Deutsch, Michael R. Berman, Matthew R. Myers, Richard A. Malinauskas

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The U.S. Food and Drug Administration recently hosted an interlaboratory study to assess the suitability and methodology of computational fluid dynamics (CFD) for demonstrating medical device safety in regulatory submissions. The benchmark study was performed in a generic medical device consisting of a 0.012 m diameter cylindrical nozzle with a sudden contraction and 10° conical diffuser, on either side of a 0.04 m long, 0.004 m diameter throat. Results from 28 simulations from around the world were compared to planar particle image velocimetry (PIV) measurements performed at three laboratories. Five flow rates were chosen that produced laminar, transitional, and turbulent regimes. In general, the CFD results showed modest agreement in global and local flow behaviors. However, all CFD data sets contained wide degrees of velocity variation in comparison to experiment and with each other, much of which could be attributed to the turbulence models used. Some of the velocity discrepancies in the sixteen three dimensional (3D) simulations resulted from substantial flow asymmetries within and downstream of the conical diffuser. Large differences in velocity symmetry were found even when using the same code and many of the same simulation parameters. In contrast, no velocity asymmetries of the same magnitude were observed in any of the planar PIV experiments; relatively minor asymmetries in one experiment were linked to slight asymmetries in the velocity profile at the inlet to the nozzle. CFD predictions of peak wall shear stress at the sudden contraction (normalized to that 0.015 m downstream) varied over two orders of magnitude, with variations of greater than 10 times even when the same software and turbulence model were used. This degree of shear stress variation will necessarily propagate through calculations of blood damage in medical devices. We conclude that CFD simulations used in qualifying medical devices for regulatory purposes need to be conducted following the best practices available, and that targeted experimental validation is essential. The results of this interlaboratory study are freely available in an internet repository (https://fdacfd.nci.nih.gov). We encourage the use of this model in further studies, and support the development of additional benchmarks, better modeling techniques, and consensus standards and guidelines for using CFD in the evaluation of medical devices.

Original languageEnglish (US)
Pages (from-to)374-391
Number of pages18
JournalCardiovascular Engineering and Technology
Volume4
Issue number4
DOIs
StatePublished - Dec 1 2013

Fingerprint

Hydrodynamics
Nozzles
Computational fluid dynamics
Benchmarking
Equipment and Supplies
Rheology
Turbulence models
Velocity measurement
Shear stress
Equipment Safety
Safety devices
Experiments
United States Food and Drug Administration
Pharynx
Practice Guidelines
Internet
Blood
Software
Flow rate
Guidelines

All Science Journal Classification (ASJC) codes

  • Biomedical Engineering
  • Cardiology and Cardiovascular Medicine

Cite this

Stewart, S. F. C., Hariharan, P., Paterson, E. G., Burgreen, G. W., Reddy, V., Day, S. W., ... Malinauskas, R. A. (2013). Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser. Cardiovascular Engineering and Technology, 4(4), 374-391. https://doi.org/10.1007/s13239-013-0166-2
Stewart, Sandy F.C. ; Hariharan, Prasanna ; Paterson, Eric G. ; Burgreen, Greg W. ; Reddy, Varun ; Day, Steven W. ; Giarra, Matthew ; Manning, Keefe B. ; Deutsch, Steven ; Berman, Michael R. ; Myers, Matthew R. ; Malinauskas, Richard A. / Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser. In: Cardiovascular Engineering and Technology. 2013 ; Vol. 4, No. 4. pp. 374-391.
@article{3d91afb848e44233af5da75b5a43e19b,
title = "Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser",
abstract = "The U.S. Food and Drug Administration recently hosted an interlaboratory study to assess the suitability and methodology of computational fluid dynamics (CFD) for demonstrating medical device safety in regulatory submissions. The benchmark study was performed in a generic medical device consisting of a 0.012 m diameter cylindrical nozzle with a sudden contraction and 10° conical diffuser, on either side of a 0.04 m long, 0.004 m diameter throat. Results from 28 simulations from around the world were compared to planar particle image velocimetry (PIV) measurements performed at three laboratories. Five flow rates were chosen that produced laminar, transitional, and turbulent regimes. In general, the CFD results showed modest agreement in global and local flow behaviors. However, all CFD data sets contained wide degrees of velocity variation in comparison to experiment and with each other, much of which could be attributed to the turbulence models used. Some of the velocity discrepancies in the sixteen three dimensional (3D) simulations resulted from substantial flow asymmetries within and downstream of the conical diffuser. Large differences in velocity symmetry were found even when using the same code and many of the same simulation parameters. In contrast, no velocity asymmetries of the same magnitude were observed in any of the planar PIV experiments; relatively minor asymmetries in one experiment were linked to slight asymmetries in the velocity profile at the inlet to the nozzle. CFD predictions of peak wall shear stress at the sudden contraction (normalized to that 0.015 m downstream) varied over two orders of magnitude, with variations of greater than 10 times even when the same software and turbulence model were used. This degree of shear stress variation will necessarily propagate through calculations of blood damage in medical devices. We conclude that CFD simulations used in qualifying medical devices for regulatory purposes need to be conducted following the best practices available, and that targeted experimental validation is essential. The results of this interlaboratory study are freely available in an internet repository (https://fdacfd.nci.nih.gov). We encourage the use of this model in further studies, and support the development of additional benchmarks, better modeling techniques, and consensus standards and guidelines for using CFD in the evaluation of medical devices.",
author = "Stewart, {Sandy F.C.} and Prasanna Hariharan and Paterson, {Eric G.} and Burgreen, {Greg W.} and Varun Reddy and Day, {Steven W.} and Matthew Giarra and Manning, {Keefe B.} and Steven Deutsch and Berman, {Michael R.} and Myers, {Matthew R.} and Malinauskas, {Richard A.}",
year = "2013",
month = "12",
day = "1",
doi = "10.1007/s13239-013-0166-2",
language = "English (US)",
volume = "4",
pages = "374--391",
journal = "Cardiovascular Engineering and Technology",
issn = "1869-408X",
publisher = "Springer Publishing Company",
number = "4",

}

Stewart, SFC, Hariharan, P, Paterson, EG, Burgreen, GW, Reddy, V, Day, SW, Giarra, M, Manning, KB, Deutsch, S, Berman, MR, Myers, MR & Malinauskas, RA 2013, 'Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser', Cardiovascular Engineering and Technology, vol. 4, no. 4, pp. 374-391. https://doi.org/10.1007/s13239-013-0166-2

Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser. / Stewart, Sandy F.C.; Hariharan, Prasanna; Paterson, Eric G.; Burgreen, Greg W.; Reddy, Varun; Day, Steven W.; Giarra, Matthew; Manning, Keefe B.; Deutsch, Steven; Berman, Michael R.; Myers, Matthew R.; Malinauskas, Richard A.

In: Cardiovascular Engineering and Technology, Vol. 4, No. 4, 01.12.2013, p. 374-391.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Results of FDA's First Interlaboratory Computational Study of a Nozzle with a Sudden Contraction and Conical Diffuser

AU - Stewart, Sandy F.C.

AU - Hariharan, Prasanna

AU - Paterson, Eric G.

AU - Burgreen, Greg W.

AU - Reddy, Varun

AU - Day, Steven W.

AU - Giarra, Matthew

AU - Manning, Keefe B.

AU - Deutsch, Steven

AU - Berman, Michael R.

AU - Myers, Matthew R.

AU - Malinauskas, Richard A.

PY - 2013/12/1

Y1 - 2013/12/1

N2 - The U.S. Food and Drug Administration recently hosted an interlaboratory study to assess the suitability and methodology of computational fluid dynamics (CFD) for demonstrating medical device safety in regulatory submissions. The benchmark study was performed in a generic medical device consisting of a 0.012 m diameter cylindrical nozzle with a sudden contraction and 10° conical diffuser, on either side of a 0.04 m long, 0.004 m diameter throat. Results from 28 simulations from around the world were compared to planar particle image velocimetry (PIV) measurements performed at three laboratories. Five flow rates were chosen that produced laminar, transitional, and turbulent regimes. In general, the CFD results showed modest agreement in global and local flow behaviors. However, all CFD data sets contained wide degrees of velocity variation in comparison to experiment and with each other, much of which could be attributed to the turbulence models used. Some of the velocity discrepancies in the sixteen three dimensional (3D) simulations resulted from substantial flow asymmetries within and downstream of the conical diffuser. Large differences in velocity symmetry were found even when using the same code and many of the same simulation parameters. In contrast, no velocity asymmetries of the same magnitude were observed in any of the planar PIV experiments; relatively minor asymmetries in one experiment were linked to slight asymmetries in the velocity profile at the inlet to the nozzle. CFD predictions of peak wall shear stress at the sudden contraction (normalized to that 0.015 m downstream) varied over two orders of magnitude, with variations of greater than 10 times even when the same software and turbulence model were used. This degree of shear stress variation will necessarily propagate through calculations of blood damage in medical devices. We conclude that CFD simulations used in qualifying medical devices for regulatory purposes need to be conducted following the best practices available, and that targeted experimental validation is essential. The results of this interlaboratory study are freely available in an internet repository (https://fdacfd.nci.nih.gov). We encourage the use of this model in further studies, and support the development of additional benchmarks, better modeling techniques, and consensus standards and guidelines for using CFD in the evaluation of medical devices.

AB - The U.S. Food and Drug Administration recently hosted an interlaboratory study to assess the suitability and methodology of computational fluid dynamics (CFD) for demonstrating medical device safety in regulatory submissions. The benchmark study was performed in a generic medical device consisting of a 0.012 m diameter cylindrical nozzle with a sudden contraction and 10° conical diffuser, on either side of a 0.04 m long, 0.004 m diameter throat. Results from 28 simulations from around the world were compared to planar particle image velocimetry (PIV) measurements performed at three laboratories. Five flow rates were chosen that produced laminar, transitional, and turbulent regimes. In general, the CFD results showed modest agreement in global and local flow behaviors. However, all CFD data sets contained wide degrees of velocity variation in comparison to experiment and with each other, much of which could be attributed to the turbulence models used. Some of the velocity discrepancies in the sixteen three dimensional (3D) simulations resulted from substantial flow asymmetries within and downstream of the conical diffuser. Large differences in velocity symmetry were found even when using the same code and many of the same simulation parameters. In contrast, no velocity asymmetries of the same magnitude were observed in any of the planar PIV experiments; relatively minor asymmetries in one experiment were linked to slight asymmetries in the velocity profile at the inlet to the nozzle. CFD predictions of peak wall shear stress at the sudden contraction (normalized to that 0.015 m downstream) varied over two orders of magnitude, with variations of greater than 10 times even when the same software and turbulence model were used. This degree of shear stress variation will necessarily propagate through calculations of blood damage in medical devices. We conclude that CFD simulations used in qualifying medical devices for regulatory purposes need to be conducted following the best practices available, and that targeted experimental validation is essential. The results of this interlaboratory study are freely available in an internet repository (https://fdacfd.nci.nih.gov). We encourage the use of this model in further studies, and support the development of additional benchmarks, better modeling techniques, and consensus standards and guidelines for using CFD in the evaluation of medical devices.

UR - http://www.scopus.com/inward/record.url?scp=84886308734&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84886308734&partnerID=8YFLogxK

U2 - 10.1007/s13239-013-0166-2

DO - 10.1007/s13239-013-0166-2

M3 - Article

AN - SCOPUS:84886308734

VL - 4

SP - 374

EP - 391

JO - Cardiovascular Engineering and Technology

JF - Cardiovascular Engineering and Technology

SN - 1869-408X

IS - 4

ER -