Hostname: page-component-848d4c4894-2pzkn Total loading time: 0 Render date: 2024-05-21T02:25:40.573Z Has data issue: false hasContentIssue false

Swimming sheet in a viscosity-stratified fluid

Published online by Cambridge University Press:  20 May 2020

Rajat Dandekar
Affiliation:
School of Mechanical Engineering, Purdue University, West Lafayette, IN 49707, USA
Arezoo M. Ardekani*
Affiliation:
School of Mechanical Engineering, Purdue University, West Lafayette, IN 49707, USA
*
Email address for correspondence: ardekani@purdue.edu

Abstract

In this work, we theoretically investigate the motion of a Taylor swimming sheet immersed in a viscosity-stratified fluid. The propulsion of the swimmer disturbs the surrounding fluid, which influences the transport of the stratifying agent described by the advection–diffusion equation. We employ a regular perturbation scheme to solve the coupled differential equations of motion up to the second order with the small parameter given by the ratio of the wave amplitude and the wavelength. The expression for the swimming velocity is linear in the magnitude of the viscosity gradient, while depending on the Péclet number in a non-monotonic way. Interestingly, we find that the Péclet number governs the propensity of the sheet to propel towards regions of favourable viscosities. In particular, for small Péclet numbers ($0<Pe<3$), the swimmer prefers regions of low viscosity, while for high Péclet numbers ($Pe>3$), the swimmer prefers regions of high viscosity. Our analysis shows that purely hydrodynamic effects might be responsible for the experimentally observed accumulation of swimmers near favourable viscosity regions. We find that viscosity gradients influence other motility characteristics of the swimmer, such as power expenditure and hydrodynamic efficiency, and provide analytical expressions for both.

Type
JFM Rapids
Copyright
© The Author(s), 2020. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ardekani, A. M. & Stocker, R. 2010 Stratlets: low Reynolds number point-force solutions in a stratified fluid. Phys. Rev. Lett. 105 (8), 084502.CrossRefGoogle Scholar
Arrigo, K. R., Robinson, D. H., Worthen, D. L., Dunbar, R. B., DiTullio, G. R., VanWoert, M. & Lizotte, M. P. 1999 Phytoplankton community structure and the drawdown of nutrients and CO2 in the Southern Ocean. Science 283 (5400), 365367.CrossRefGoogle ScholarPubMed
Berg, H. 2004 E. coli in Motion. Springer.CrossRefGoogle Scholar
Blake, J. R. 1971 A spherical envelope approach to ciliary propulsion. J. Fluid Mech. 46 (1), 199208.CrossRefGoogle Scholar
Boufadel, M. C., Suidan, M. T. & Venosa, A. D. 1999 A numerical model for density-and-viscosity-dependent flows in two-dimensional variably saturated porous media. J. Contam. Hydrol. 37 (1–2), 120.CrossRefGoogle Scholar
Candelier, F., Mehaddi, R. & Vauquelin, O. 2014 The history force on a small particle in a linearly stratified fluid. J. Fluid Mech. 749, 184200.CrossRefGoogle Scholar
Dandekar, R., Shaik, V. A. & Ardekani, A. M. 2019 Swimming sheet in a density-stratified fluid. J. Fluid Mech. 874, 210234.CrossRefGoogle Scholar
Daniels, M. J., Longland, J. M. & Gilbart, J. 1980 Aspects of motility and chemotaxis in spiroplasmas. Microbiology 118 (2), 429436.CrossRefGoogle Scholar
Datt, C. & Elfring, G. J. 2019 Active particles in viscosity gradients. Phys. Rev. Lett. 123 (15), 158006.CrossRefGoogle ScholarPubMed
Doostmohammadi, A., Stocker, R. & Ardekani, A. M. 2012 Low-Reynolds-number swimming at pycnoclines. Proc. Natl Acad. Sci. USA 109 (10), 38563861.CrossRefGoogle ScholarPubMed
Du, J., Keener, J. P., Guy, R. D. & Fogelson, A. L. 2012 Low-Reynolds-number swimming in viscous two-phase fluids. Phys. Rev. E 85 (3), 036304.Google ScholarPubMed
Fauci, L. J. & Dillon, R. 2006 Biofluidmechanics of reproduction. Annu. Rev. Fluid Mech. 38, 371394.CrossRefGoogle Scholar
Fredericks, W. J., Hammonds, M. C., Howard, S. B. & Rosenberger, F. 1994 Density, thermal expansivity, viscosity and refractive index of lysozyme solutions at crystal growth concentrations. J. Cryst. Growth 141 (1-2), 183192.CrossRefGoogle Scholar
Jacquemin, J., Husson, P., Padua, A. A. & Majer, V. 2006 Density and viscosity of several pure and water-saturated ionic liquids. Green Chem. 8 (2), 172180.CrossRefGoogle Scholar
Kirkman-Brown, J. C. & Smith, D. J. 2011 Sperm motility: is viscosity fundamental to progress? Mol. Hum. Reprod. 17 (8), 539544.CrossRefGoogle Scholar
Lauga, E. 2007 Propulsion in a viscoelastic fluid. Phys. Fluids 19 (8), 083104.CrossRefGoogle Scholar
Lauga, E. & Powers, T. R. 2009 The hydrodynamics of swimming microorganisms. Rep. Prog. Phys. 72 (9), 096601.Google Scholar
Leal, L. 2007 Advanced Transport Phenomena: Fluid Mechanics and Convective Transport Processes, vol. 7. Cambridge University Press.CrossRefGoogle Scholar
Leshansky, A. M. 2009 Enhanced low-Reynolds-number propulsion in heterogeneous viscous environments. Phys. Rev. E 80 (5), 051911.Google ScholarPubMed
Lewis, O. L., Keener, J. P. & Fogelson, A. L. 2017 A physics-based model for maintenance of the pH gradient in the gastric mucus layer. Am. J. Physiol. Gastrointest. Liver Physiol. 313 (6), G599G612.CrossRefGoogle Scholar
Li, G. & Ardekani, A. M. 2015 Undulatory swimming in non-Newtonian fluids. J. Fluid Mech. 784, 486505.CrossRefGoogle Scholar
Liebchen, B., Monderkamp, P., ten Hagen, B. & Löwen, H. 2018 Viscotaxis: microswimmer navigation in viscosity gradients. Phys. Rev. Lett. 120 (20), 208002.CrossRefGoogle ScholarPubMed
Lighthill, M. J. 1952 On the squirming motion of nearly spherical deformable bodies through liquids at very small Reynolds numbers. Commum. Pure Appl. Maths 5 (2), 109118.CrossRefGoogle Scholar
Mirbagheri, S. A. & Fu, H. C. 2016 Helicobacter pylori couples motility and diffusion to actively create a heterogeneous complex medium in gastric mucus. Phys. Rev. Lett. 116 (19), 198101.CrossRefGoogle ScholarPubMed
Nganguia, H. & Pak, O. S. 2018 Squirming motion in a Brinkman medium. J. Fluid Mech. 855, 554573.CrossRefGoogle Scholar
Petrino, M. G. & Doetsch, R. N. 1978 ‘Viscotaxis’, a new behavioural response of Leptospira interrogans (biflexa) strain b16. Microbiology 109 (1), 113117.Google ScholarPubMed
Sherman, M. Y., Timkina, E. O. & Glagolev, A. N. 1982 Viscosity taxis in Escherichia coli. FEMS Microbiol. Lett. 13 (2), 137140.CrossRefGoogle Scholar
Shoele, K. & Eastham, P. S. 2018 Effects of nonuniform viscosity on ciliary locomotion. Phys. Fluids 3 (4), 043101.Google Scholar
Stehnach, M. R.2019 The dispersal of swimming microalgae in inhomogeneous viscous environments. PhD thesis, Tufts University, Medford and Somerville, MA.Google Scholar
Stewart, P. S. 2012 Mini-review: convection around biofilms. Biofouling 28 (2), 187198.CrossRefGoogle ScholarPubMed
Sznitman, J., Purohit, P. K., Krajacic, P., Lamitina, T. & Arratia, P. E. 2010 Material properties of Caenorhabditis elegans swimming at low Reynolds number. Biophys. J. 98 (4), 617626.CrossRefGoogle ScholarPubMed
Takabe, K., Tahara, H., Islam, M. S., Affroze, S., Kudo, S. & Nakamura, S. 2017 Viscosity-dependent variations in the cell shape and swimming manner of Leptospira. Microbiology 163 (2), 153160.CrossRefGoogle ScholarPubMed
Taylor, G. I. 1951 Analysis of the swimming of microscopic organisms. Proc. R. Soc. Lond. A 209 (1099), 447461.Google Scholar