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Viscous entrainment on hairy surfaces
Phys. Rev. Fluids 3, 024002 – Published 7 February, 2018
DOI: https://doi.org/10.1103/PhysRevFluids.3.024002
Abstract
Nectar-drinking bats and honeybees have tongues covered with hairlike structures, enhancing their ability to take up viscous nectar by dipping. Using a combination of model experiments and theory, we explore the physical mechanisms that govern viscous entrainment in a hairy texture. Hairy surfaces are fabricated using laser cut molds and casting samples with polydimethylsiloxane (PDMS) elastomer. We model the liquid trapped within the texture using a Darcy-Brinkmann-like approach and derive the drainage flow solution. The amount of fluid that is entrained is dependent on the viscosity of the fluid, the density of the hairs, and the withdrawal speed. Both experiments and theory reveal an optimal hair density to maximize fluid uptake.
Physics Subject Headings (PhySH)
Synopsis
How Hairy Tongues Help Bats Drink Nectar
Experiments and theory show that hairs on a bat’s tongue allow the animal to drink 10 times more nectar than it could if its tongue were smooth.
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References (17)
- W. Kim and J. W. M. Bush, Natural drinking strategies, J. Fluid Mech. 705, 7 (2012).
- W. Kim, F. Peaudecerf, M. W. Baldwin, and J. W. M. Bush, The hummingbird's tongue: A self-assembling capillary syphon, Proc. R. Soc. B 279, 4990 (2012).
- P. M. Reis, S. Jung, J. M. Aristoff, and R. Stocker, How cats lap: Water uptake by Felis catus, Science 330, 1231 (2010).
- W. Kim, T. Gilet, and J. W. M. Bush, Optimal concentrations in nectar feeding, Proc. Natl. Acad. Sci. USA 108, 16618 (2011).
- C. J. Harper, S. M. Swartz, and E. L. Brainerd, Specialized bat tongue is a hemodynamic nectar mop, Proc. Natl. Acad. Sci. USA 110, 8852 (2013).
- L. Landau and B. Levich, Dragging of a liquid by a moving plate, Acta Physicochim. URSS 17, 42 (1942).
- B. Derjaguin, On the thickness of the liquid film adhering to the walls of a vessel after emptying, Prog. Surf. Sci. 43, 134 (1993).
- F. Brau, D. Lanterbecq, L.-N. Zghikh, V. Bels, and P. Damman, Dynamics of prey prehension by chameleons through viscous adhesion, Nat. Phys. 12, 931 (2016).
- H. Yang, J. Wu, and S. Yan, Effects of erectable glossal hairs on a honeybee's nectar-drinking strategy, Appl. Phys. Lett. 104, 263701 (2014).
- J. Zhao, J. Wu, and S. Yan, Erection mechanism of glossal hairs during honeybee feeding, J. Theor. Biol. 386, 62 (2015).
- K. C. Richardson, R. D. Wooller, and B. G. Collins, Adaptations to a diet of nectar and pollen in the marsupial Tarsipes rostratus (Marsupialia: Tarsipedidae), J. Zool. 208, 285 (1986).
- J. Seiwert, C. Clanet, and D. Quéré, Coating of a textured solid, J. Fluid Mech. 669, 55 (2011).
- A. Nasto, M. Regli, P.-T. Brun, J. Alvarado, C. Clanet, and A. E. Hosoi, Air entrainment in hairy surfaces, Phys. Rev. Fluids 1, 033905 (2016).
- E. Guyon, Physical Hydrodynamics (Oxford University Press, New York, 2001).
- J. F. Swindells, Viscosities of Sucrose Solutions at Various Temperatures: Tables of Recalculated Values (US GPO, Washington, DC, 1958), Vol. 440.
- C. Zhao, J. Wu, and S. Yan, Observations and temporal model of a honeybee's hairy tongue in microfluid transport, J. Appl. Phys. 118, 194701 (2015).
- C. Ishino, M. Reyssat, E. Reyssat, K. Okumura, and D. Quere, Wicking within forests of micropillars, Europhys. Lett. 79, 56005 (2007).
