The rheology dependent region in turbulent pipe flow of a Generalised Newtonian fluid

Jagmohan Singh, M. Rudman, H. M. Blackburn

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Direct numerical simulations (DNS) of turbulent pipe flow of a Generalised Newtonian (GN) fluid at Reτ = 323 are analysed to identify the region where GN rheology has the major influence. The flow domain is divided into two parts: in y+ < y+up and y+ > y+up, with the viscosity modelled using a power-law rheology for y+ < y+up and a uniform viscosity for y+ > y+up. Values for y+up of 35 and 70 are considered. Results show that beyond y+ = 70, the GN rheology has no significant effect on the mean flow or turbulence statistics, and that the effect of GN rheology is confined to the near wall. To understand these results, the turbulent kinetic energy budget of the GN fluid and a Newtonian fluid at the same Reτ = 323 are compared. The comparison shows that the GN viscosity-dependent terms in the balance either vanish or do not show rheology dependence beyond y+ = 70. The current results imply that in Reynolds averaged Navier–Stokes and Large eddy simulations the GN rheology’s effects can be taken care of by modifying the wall functions.

Original languageEnglish
Title of host publicationProceedings of the 20th Australasian Fluid Mechanics Conference (AFMC)
Place of PublicationPerth WA Australia
PublisherAustralasian Fluid Mechanics Society
Number of pages4
ISBN (Electronic)9781740523776
ISBN (Print)9781740523776
Publication statusPublished - 2016
EventAustralasian Fluid Mechanics Conference 2016 - The University of Western Australia, Perth, Australia
Duration: 5 Dec 20168 Dec 2016
Conference number: 20th

Publication series

NameProceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016


ConferenceAustralasian Fluid Mechanics Conference 2016
Abbreviated titleAFMC 2016

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