Study of laminar-turbulent flow transition under pulsatile conditions in a constricted channel

In this paper, direct numerical simulation is performed to investigate a pulsatile flow in a constricted channel to gain physical insights into laminar-turbulent-laminar flow transitions. An in-house computer code is used to conduct numerical simulations based on available high-performance shared me...

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Bibliographic Details
Published in:International journal of computational fluid dynamics Vol. 29; no. 9-10; pp. 447 - 463
Main Authors: Khair, Abul, Wang, Bing-Chen, Kuhn, David C.S.
Format: Journal Article
Language:English
Published: Taylor & Francis 21.10.2015
Subjects:
Channels
Computational fluid dynamics
constricted channel
Constrictions
Fluid flow
Kinetic energy
Laminar
pulsatile flow
simulation
transition
Turbulence
Turbulent flow
ISSN:1061-8562, 1029-0257
Online Access:Get full text
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Summary:In this paper, direct numerical simulation is performed to investigate a pulsatile flow in a constricted channel to gain physical insights into laminar-turbulent-laminar flow transitions. An in-house computer code is used to conduct numerical simulations based on available high-performance shared memory parallel computing facilities. The Womersley number tested is fixed to 10.5 and the Reynolds number varies from 500 to 2000. The influences of the degree of stenosis and pulsatile conditions on flow transitions and structures are investigated. In the region upstream of the stenosis, the flow pattern is primarily laminar. Immediately after the stenosis, the flow recirculates under an adverse streamwise pressure gradient, and the flow pattern transitions from laminar to turbulent. In the region far downstream of the stenosis, the flow becomes re-laminarised. The physical characteristics of the flow field have been thoroughly analysed in terms of the mean streamwise velocity, turbulence kinetic energy, viscous wall shear stresses, wall pressure and turbulence kinetic energy spectra.
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ISSN:1061-8562
1029-0257
DOI:10.1080/10618562.2015.1130222