Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids
In this study, we have considered the modal and non-modal stability of fluids with shear-dependent viscosity flowing in a rigid straight pipe. A second order finite-difference code is used for the simulation of pipe flow in the cylindrical coordinate system. The Carreau-Yasuda model where the rheolo...
Main Author: | |
---|---|
Format: | Others |
Language: | English |
Published: |
Linköpings universitet, Mekanisk värmeteori och strömningslära
2012
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82037 |
id |
ndltd-UPSALLA1-oai-DiVA.org-liu-82037 |
---|---|
record_format |
oai_dc |
spelling |
ndltd-UPSALLA1-oai-DiVA.org-liu-820372013-01-08T13:44:18ZInstabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening FluidsengSadrizadeh, SasanLinköpings universitet, Mekanisk värmeteori och strömningsläraLinköpings universitet, Tekniska högskolan2012StabilityPulsatile pipeTransient GrowthFloquet MultiplierModal and non-Modal StabilityIn this study, we have considered the modal and non-modal stability of fluids with shear-dependent viscosity flowing in a rigid straight pipe. A second order finite-difference code is used for the simulation of pipe flow in the cylindrical coordinate system. The Carreau-Yasuda model where the rheological parameters vary in the range of 0.3 < n < 1.5 and 0.1 < λ < 100 is represents the viscosity of shear- thinning and shear thickening fluids. Variation of the periodic pulsatile forcing is obtained via the ratio Kω/Kο and set between 0.2 and 20. Zero and non-zero streamwise wavenumber have been considered separately in this study. For the axially invariant mode, energy growth maxima occur for unity azimuthal wave number, whereas for the axially non-invariant mode, maximum energy growth can be observed for azimuthal wave number of two for both Newtonian and non-Newtonian fluids. Modal and non-modal analysis for both Newtonian and non-Newtonian fluids show that the flow is asymptotically stable for any configuration and the pulsatile flow is slightly more stable than steady flow. Increasing the maximum velocity for shear-thinning fluids caused by reducing power-low index n is more evident than shear-thickening fluids. Moreover, rheological parameters of Carreau-Yasuda model have ignored the effect on the peak velocity of the oscillatory components. Increasing Reynolds number will enhance the maximum energy growth while a revers behavior is observed by increasing Womersley number. Student thesisinfo:eu-repo/semantics/bachelorThesistexthttp://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82037application/pdfinfo:eu-repo/semantics/openAccess |
collection |
NDLTD |
language |
English |
format |
Others
|
sources |
NDLTD |
topic |
Stability Pulsatile pipe Transient Growth Floquet Multiplier Modal and non-Modal Stability |
spellingShingle |
Stability Pulsatile pipe Transient Growth Floquet Multiplier Modal and non-Modal Stability Sadrizadeh, Sasan Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
description |
In this study, we have considered the modal and non-modal stability of fluids with shear-dependent viscosity flowing in a rigid straight pipe. A second order finite-difference code is used for the simulation of pipe flow in the cylindrical coordinate system. The Carreau-Yasuda model where the rheological parameters vary in the range of 0.3 < n < 1.5 and 0.1 < λ < 100 is represents the viscosity of shear- thinning and shear thickening fluids. Variation of the periodic pulsatile forcing is obtained via the ratio Kω/Kο and set between 0.2 and 20. Zero and non-zero streamwise wavenumber have been considered separately in this study. For the axially invariant mode, energy growth maxima occur for unity azimuthal wave number, whereas for the axially non-invariant mode, maximum energy growth can be observed for azimuthal wave number of two for both Newtonian and non-Newtonian fluids. Modal and non-modal analysis for both Newtonian and non-Newtonian fluids show that the flow is asymptotically stable for any configuration and the pulsatile flow is slightly more stable than steady flow. Increasing the maximum velocity for shear-thinning fluids caused by reducing power-low index n is more evident than shear-thickening fluids. Moreover, rheological parameters of Carreau-Yasuda model have ignored the effect on the peak velocity of the oscillatory components. Increasing Reynolds number will enhance the maximum energy growth while a revers behavior is observed by increasing Womersley number. |
author |
Sadrizadeh, Sasan |
author_facet |
Sadrizadeh, Sasan |
author_sort |
Sadrizadeh, Sasan |
title |
Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
title_short |
Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
title_full |
Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
title_fullStr |
Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
title_full_unstemmed |
Instabilities in Pulsating Pipe Flow of Shear-Thinning and Shear-Thickening Fluids |
title_sort |
instabilities in pulsating pipe flow of shear-thinning and shear-thickening fluids |
publisher |
Linköpings universitet, Mekanisk värmeteori och strömningslära |
publishDate |
2012 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-82037 |
work_keys_str_mv |
AT sadrizadehsasan instabilitiesinpulsatingpipeflowofshearthinningandshearthickeningfluids |
_version_ |
1716527492122017792 |