English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Autorotation of botanical samaras, with a consequent reduction in their rate of descent, increases dispersal range in the presence of horizontal winds. Samaras in initial free fall from rest pass through a brief transitional phase prior to reaching their minimum rate of descent and stable autorotation. By contrast, intense wind gusts and elastic recoil of tree branches can produce impulsive samara detachment and accelerate them rapidly through the air. Here, we investigate the autorotation of maple samaras when launched with a high initial impulse. Norway maple seeds catapulted either vertically or horizontally at approximately 9 m s−1 exhibited remarkably high and rapid decelerations (10–15g ) and reached a near-zero translational speed in less than 150 ms. The initial rotational frequency of catapulted seeds was up to four times greater than that ultimately reached during steady-state autorotation. These helicopter seeds thus transiently produce very high lift forces (at Reynolds numbers near approximately 104 ) that act to enhance aerial transport. These findings are relevant to the modelling of long-distance seed dispersal in unsteady flows, as well as to the design of deceleration mechanisms based on lift generation, rather than drag-based devices such as parachutes.

Superb autorotator: rapid decelerations in impulsively launched samaras