Transition to turbulence in an oscillatory flow through stenosis

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Onset of flow transition in a sinusoidally oscillating flow through a rigid, constant area circular pipe with a smooth sinusoidal obstruction in the center of the pipe is studied by performing direct numerical simulations, with resolutions close to the Kolmogorov microscales. The studied pipe is stenosed in the center with a 75% reduction in area in two distinct configurations—one that is symmetric to the axis of the parent pipe and the other that is offset by 0.05 diameters to introduce an eccentricity, which disturbs the flow thereby triggering the onset of flow transition. The critical Reynolds number at which the flow transitions to turbulence for a zero-mean oscillatory flow through a stenosis is shown to be nearly tripled in comparison with studies of pulsating unidirectional flow through the same stenosis. The onset of transition is further explored with three different flow pulsation frequencies resulting in a total of 90 simulations conducted on a supercomputer. It is found that the critical Reynolds number at which the oscillatory flow transitions is not affected by the pulsation frequencies. The locations of flow breakdown and re-stabilization post-stenosis are, however, respectively shifted closer to the stenosis throat with increasing pulsation frequencies. The results show that oscillatory physiological flows, while more stable, exhibit fluctuations due to geometric complexity and have implications in studies of dispersion and solute transport in the cerebrospinal fluid flow and understanding of pathological conditions.

Original languageEnglish
Number of pages19
JournalBiomechanics and modeling in mechanobiology
DOIs
Publication statusE-pub ahead of print/First online - 30 Jul 2019
Externally publishedYes

Fingerprint

Transition to Turbulence
Transition flow
Oscillatory Flow
Stenosis
Pathologic Constriction
Turbulence
Pipe
Reynolds number
Oscillating flow
Cerebrospinal fluid
Solute transport
Pulsatile Flow
Supercomputers
Direct numerical simulation
Pharynx
Cerebrospinal Fluid
Flow of fluids
Stabilization
Solute Transport
Eccentricity

Keywords

  • Kolmogorov scale
  • Lattice Boltzmann method
  • Stenosis
  • Transitional flow

Cite this

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title = "Transition to turbulence in an oscillatory flow through stenosis",
abstract = "Onset of flow transition in a sinusoidally oscillating flow through a rigid, constant area circular pipe with a smooth sinusoidal obstruction in the center of the pipe is studied by performing direct numerical simulations, with resolutions close to the Kolmogorov microscales. The studied pipe is stenosed in the center with a 75{\%} reduction in area in two distinct configurations—one that is symmetric to the axis of the parent pipe and the other that is offset by 0.05 diameters to introduce an eccentricity, which disturbs the flow thereby triggering the onset of flow transition. The critical Reynolds number at which the flow transitions to turbulence for a zero-mean oscillatory flow through a stenosis is shown to be nearly tripled in comparison with studies of pulsating unidirectional flow through the same stenosis. The onset of transition is further explored with three different flow pulsation frequencies resulting in a total of 90 simulations conducted on a supercomputer. It is found that the critical Reynolds number at which the oscillatory flow transitions is not affected by the pulsation frequencies. The locations of flow breakdown and re-stabilization post-stenosis are, however, respectively shifted closer to the stenosis throat with increasing pulsation frequencies. The results show that oscillatory physiological flows, while more stable, exhibit fluctuations due to geometric complexity and have implications in studies of dispersion and solute transport in the cerebrospinal fluid flow and understanding of pathological conditions.",
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author = "Kartik Jain",
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Transition to turbulence in an oscillatory flow through stenosis. / Jain, Kartik .

In: Biomechanics and modeling in mechanobiology, 30.07.2019.

Research output: Contribution to journalArticleAcademicpeer-review

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