Elementary flow field profiles of micro-swimmers in weakly anisotropic nematic fluids : Stokeslet, stresslet, rotlet and source flows

Kos, Žiga (author), Ravnik, Miha (author)

Analytic formulations of elementary flow field profiles in weakly anisotropic nematic fluid are determined, which can be attributed to biological or artificial micro-swimmers, including Stokeslet, stresslet, rotlet and source flows. Stokes equation for a nematic stress tensor is written with the Green function and solved in the k-space for anisotropic Leslie viscosity coefficients under the limit of leading isotropic viscosity coefficient. Analytical expressions for the Green function are obtained that are used to compute the flow of monopole or dipole swimmers at various alignments of the swimmers with respect to the homogeneous director field. Flow profile is also solved for the flow sources/sinks and source dipoles showing clear emergence of anisotropy in the magnitude of flow profile as the result of fluid anisotropic viscosity. The range of validity of the presented analytical solutions is explored, as compared to exact numerical solutions of the Stokes equation. This work is a contribution towards understanding elementary flow motifs and profiles in fluid environments that are distinctly affected by anisotropic viscosity, offering analytic insight, which could be of relevance to a range of systems from microswimmers, active matter to microfluidics.

• Language: English
• Keywords: fluid dynamics, nematic fluids, anisotropic fluids, elementary flow field profiles, anisotropy, micro-swimmers, nematic, non-Newtonian fluids
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2018
• Number of pages: 19 str.
• Numbering: Vol. 3, iss. 1, art. 15
• PID: 20.500.12556/RUL-131873
• UDC: 532.5
• ISSN on article: 2311-5521
• DOI: 10.3390/fluids3010015
• COBISS.SI-ID: 3169124
• Publication date in RUL: 05.10.2021

KOS, Žiga and RAVNIK, Miha, 2018, Elementary flow field profiles of micro-swimmers in weakly anisotropic nematic fluids : Stokeslet, stresslet, rotlet and source flows. Fluids [online]. 2018. Vol. 3, no. 1,  15. [Accessed 26 April 2025]. DOI 10.3390/fluids3010015. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=131873

Record is a part of a journal

• Title: Fluids
• Shortened title: Fluids
• Publisher: MDPI AG
• ISSN: 2311-5521
• COBISS.SI-ID: 525935385

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 01.03.2018

Secondary language

• Language: Slovenian
• Keywords: dinamika tekočin, nematske tekočine, anizotropne tekočine