| Spatio-temporal instabilities in viscoelastic channel flows: The centre mode | |
Wan, Dongdong; Sun, Guangrui; Xu D(徐多) ; Zhang, Mengqi; Shu, Chang
| |
| Source Publication | JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
 |
| 2023-09-01 | |
| Volume | 319Pages:105072 |
| ISSN | 0377-0257 |
| Abstract | We study in this work the spatio-temporal characteristics of the centre-mode linear instability in viscoelastic channel flows of Oldroyd-B and FENE-P fluids. The linear complex Ginzburg-Landau equation derived using an amplitude expansion method is adopted to determine whether the flow is convectively unstable or absolutely unstable. Comparison of the obtained results with those from the conventional saddle-point searching method shows a favourable agreement. This demonstrates the good predictability of the linear complex Ginzburg- Landau equation which is more suitable for a parametric study in a large space than the conventional method. We found that the centre-mode instability in the viscoelastic channel flow is of a convective nature, i.e., the trailing edge of the wavepacket travels downstream. This could be attributed to the relatively high phase speed, low spreading rate and low growth rate of the instability, collectively preventing a disturbance from travelling upstream. Our results show that stronger polymer elasticity (a greater elasticity number or larger polymer concentration) marginally affects the trailing-edge velocity of the centre mode. Decreasing the maximum polymer extensibility in the FENE-P model reduces the spreading rate of the wavepacket and makes the centre-mode disturbance more convective. Theoretical derivations at asymptotically high Reynolds numbers confirm the convective nature of the instabilities from numerical observations. Our results may be conducive to a better understanding of the spatio-temporal instability in viscoelastic experiments. |
| Keyword | Viscoelastic fluids Channel flows Spatio-temporal instability Ginzburg-Landau equation |
| DOI | 10.1016/j.jnnfm.2023.105072 |
| Indexed By | SCI ; EI |
| Language | 英语 |
| WOS ID | WOS:001020747900001 |
| WOS Research Area | Mechanics |
| WOS Subject | Mechanics |
| Funding Organization | China Scholarship Council [201906220200] ; NUS research scholarship ; NUS (Suzhou) Research Institute ; National Natural Science Foundation of China [12202300, 92152106] |
| Classification | 二类 |
| Ranking | 3+ |
| Contributor | Zhang, MQ (corresponding author), Natl Univ Singapore, Dept Mech Engn, 9 Engn Dr 1, Singapore 117575, Singapore. |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/92573 |
| Collection | 非线性力学国家重点实验室 |
| Affiliation | 1.{Wan, Dongdong, Sun, Guangrui, Zhang, Mengqi, Shu, Chang} Natl Univ Singapore, Dept Mech Engn, 9 Engn Dr 1, Singapore 117575, Singapore 2.{Xu, Duo} Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China 3.{Xu, Duo} Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China |
| Recommended Citation GB/T 7714 | Wan, Dongdong,Sun, Guangrui,Xu D,et al. Spatio-temporal instabilities in viscoelastic channel flows: The centre mode[J]. JOURNAL OF NON-NEWTONIAN FLUID MECHANICS,2023,319:105072.Rp_Au:Zhang, MQ (corresponding author), Natl Univ Singapore, Dept Mech Engn, 9 Engn Dr 1, Singapore 117575, Singapore. |
| APA | Wan, Dongdong,Sun, Guangrui,徐多,Zhang, Mengqi,&Shu, Chang.(2023).Spatio-temporal instabilities in viscoelastic channel flows: The centre mode.JOURNAL OF NON-NEWTONIAN FLUID MECHANICS,319,105072. |
| MLA | Wan, Dongdong,et al."Spatio-temporal instabilities in viscoelastic channel flows: The centre mode".JOURNAL OF NON-NEWTONIAN FLUID MECHANICS 319(2023):105072. |
| Files in This Item: | Download All | |||||
| File Name/Size | DocType | Version | Access | License | ||
| Jp2023Fa194.pdf（1257KB） | 期刊论文 | 出版稿 | 开放获取 | CC BY-NC-SA | View Download | |
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment