VGU RESEARCH REPOSITORY
Please use this identifier to cite or link to this item:
https://epub.vgu.edu.vn/handle/dlibvgu/748
DC Field | Value | Language |
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dc.contributor.author | Tung Duong | en_US |
dc.date.accessioned | 2020-03-12T17:08:54Z | - |
dc.date.available | 2020-03-12T17:08:54Z | - |
dc.date.issued | 2019 | - |
dc.identifier.uri | http://epub.vgu.edu.vn/handle/dlibvgu/748 | - |
dc.description.abstract | In this thesis we study the flow of non-Newtonian fluid over a circular cylinder near a solid wall. The wall is moving at the same velocity as the fluid at inlet. This setting is similar to the motion of a probe, a sensor or a needle in a bounded region of polymer gel or emulsion, or a remotely-operated underwater vehicle moving against still sediment near the seabed. The fluid is non-Newtonian, a yield stress one with some shear thinning property. It is represented using the Herschel-Bulkley model. The problem is two-dimensional and ANSYS Fluent is utilized. At first, simulations of the flow over the cylinder without the presence of the wall are carried out. The results are validated against both the experimental and numerical ones obtained by Mossaz et al. [J. Non-Newtonian Fluid Mech. 189-190 (2012) 40–52] at Reynolds number, Re, below 45. Then, the wall is introduced into the simulation domain. Simulations with the wall at various gap, typically G/D = 1, 2, 4 and 10 with G being the gap and D the cylinder’s diameter, are performed. Re is 60, which is in the range a conventional/Newtonian fluid flow would exhibit some von-Karman vortex street. Detailed analysis of the influence of the gap in the flow is carried out. It is found that only when the gap is sufficiently small, i.e. G/D = 1, vortex shedding behind the cylinder is observed at Re = 60 and Oldroyd number Od = 0.32 for a shear thinning fluid with a yield stress of 0 = 1.88 Pa. Moreover, drag and lift force coefficients are reported as a function of G/D. They are found to increase when the gap gets smaller. Finally, effect of the Oldroyd number is also investigated. Three values of Od, i.e. Od = 0.17, 0.20 and 0.24, are realized. It is found that large Od reduces the instability of the flow, lessening its unsteady characteristics. In addition, drag force coefficient is found to increase with the increasing of Od | en_US |
dc.language.iso | en_US | en_US |
dc.publisher | Vietnamese - German University | en_US |
dc.subject | Non-Newtonian fluid | en_US |
dc.subject | Circular cylinder | en_US |
dc.subject | Solid wall | en_US |
dc.subject | Herschel-Bulkley model | en_US |
dc.title | Study of a non – Newtonian fluid flow over a cylinder near a moving wall | en_US |
dc.type | Thesis | en_US |
item.grantfulltext | restricted | - |
item.fulltext | With Fulltext | - |
item.languageiso639-1 | other | - |
Appears in Collections: | Computational Engineering (CompEng) |
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Study of a non-newtonian fluid flow over a cylinder near a moving wall.pdf | 2.77 MB | Adobe PDF |
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