Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Research Highlight
  • Published:

FLUID DYNAMICS

Raindrops falling on pine needles

Nature Reviews Physics volume 2, page 600 (2020)Cite this article

Subjects

Pine needles need to be able to shed water to avoid their pores becoming waterlogged when it rains, which can lead to disease. How this happens has previously been studied using idealized fibres with circular cross-sections, but pine needles have wedge-shaped cross-sections. Writing in Physics of Fluids, Amy Lebanoff and Andrew Dickerson report that a wedge shape is more effective at shedding water than a round one is. Understanding water-shedding in nature is also useful when designing hydrophobic surfaces.

The experiment was done by either dropping water onto the wedge-up side of the needle or onto the round-up side of the needle. For a fixed drop size, the wedge-up fibres are more effective at splitting the drop into smaller droplets than their round-up counterparts. The impact force felt by the wedge-up fibres is larger, but the amount of water retained on the fibre is much lower. From an evolutionary context, the trade-off between impact force and water shedding is important as high-impact water drops can also damage the needles. This study indicates that the importance of water-shedding dominates in this case. Pine species that have more needles per bud, and so smaller wedge-angles per needle, are more effective at splitting incoming drops and shedding water.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

References

Original article

  • Lebanoff, A. & Dickerson, A. Drop impact onto pine needle fibers with non-circular cross section. Physics of Fluids 32, 092113 (2020)

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Nature Reviews Physics https://www.nature.com/natrevphys/

    Ankita Anirban

Authors
  1. Ankita Anirban
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ankita Anirban.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Anirban, A. Raindrops falling on pine needles. Nat Rev Phys 2, 600 (2020). https://doi.org/10.1038/s42254-020-00253-7

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s42254-020-00253-7

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing