Passive appendages generate drift through symmetry breaking
2014 (English)In: Nature Communications, ISSN 2041-1723, Vol. 5, 5310- p.Article in journal (Refereed) Published
Plants and animals use plumes, barbs, tails, feathers, hairs and fins to aid locomotion. Many of these appendages are not actively controlled, instead they have to interact passively with the surrounding fluid to generate motion. Here, we use theory, experiments and numerical simulations to show that an object with a protrusion in a separated flow drifts sideways by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in a fluid flow is unstable and how it stabilizes either to the left or right of the incoming flow direction. It is plausible that organisms with appendages in a separated flow use this newly discovered mechanism for locomotion; examples include the drift of plumed seeds without wind and the passive reorientation of motile animals.
Place, publisher, year, edition, pages
Nature Publishing Group, 2014. Vol. 5, 5310- p.
Reynolds-Number, Soap Film, Flows, Fluid, Cylinder, Forces, Body
Other Engineering and Technologies
IdentifiersURN: urn:nbn:se:kth:diva-157216DOI: 10.1038/ncomms6310ISI: 000344061600001ScopusID: 2-s2.0-84923335171OAI: oai:DiVA.org:kth-157216DiVA: diva2:769747
FunderSwedish Research Council, VR-2010-3910
QC 201412092014-12-092014-12-082015-01-19Bibliographically approved