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Notice the doming of some spider webs in wind; such indicates that the wind and silks of the spider web are interacting; net resistance occurs; if the wind is too great, the spider web doming bursts as some lines break. We see smoke tests on spider lines. And we seek formation of natural non-linear dynamic disturbances of spider silk threads wafted in the wind. A silk wafting in real airs cannot be perfectly straight; what happens when non-straightness occurs relative to the aerodynamics of the silk? http://www.thetimes.co.uk/tto/multimedi ... 07936c.jpg
Significant article: http://www.americanarachnology.org/JoA_free/JoA_v27_n1/arac_27_01_0281.pdf
AN AERIAL LOTTERY: THE PHYSICS OF BALLOONING IN A CHAOTIC ATMOSPHERE
Robert B. Suter: Department of Biology, Vassar College, Poughkeepsie, New York 12604 USA
physics underlying ballooning. Two subsequent
studies, both empirical investigations of drag
on spiders and their silk (Suter 1991, 1992),
have sharpened the picture somewhat. As a
result of these three studies, we now know (1)
that only very small spiders can rely on ballooning
for dispersal over large distances, (2)
that both silk and the spider itself (especially
the legs) provide the drag necessary to become
airborne, and (3) that the spider has both
postural and silk-length control over the magnitude
of the drag forces. We also have both
theoretical (Humphrey 1987) and empirical
(Suter 1991) equations describing the relationships
among silk length, spider mass, drag,
and terminal velocity.
Kiting spiders? Many considerations about the lines involved. While so considering, add in the static concern: How can electrostatic forces provide lift to the gossamer spider? I am wondering if the aggregate of silks tossed out have the same electrical charge; like charges repel; and maybe individual silks might repel each other forming a kind of cone effect with perhaps slowed air inside the group of silks; the aggregate body of air and silk might then interact with wind and thermals as a "body' of a wing.
http://www.thetimes.co.uk/tto/weather/article4442980.ece
Drag of lines set traverse to the wind have been studied. Bring such forward as is interesting. Total drag cost of a line system on a given hang glider?
Etc.
Wind induces variations in spider web geometry and sticky spiral droplet volume
Chao-Chia Wu, Sean J. Blamires, Chung-Lin Wu, I-Min Tso
Journal of Experimental Biology 2013 216: 3342-3349; doi: 10.1242/jeb.083618
Cheryl Hayashi: The magnificence of spider silk
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One day there may be discussion on just how much spider silk is used in a hang glider system ...
So far, my sum: "balloon" could better be "kite" for the ballooning spider; I see the silks forming wing being kite anchored by the spider body; then also, in the dynamic the spider body become wing anchored to the silk complex aggregate. As with any kite system: set of anchors (wings) tethered to set of wings. Opposing wing sets are tethered by a tether set.
================== filler: Some lines were sucked up:
Read more: http://www.dailymail.co.uk/news/article-436584/Amazing-escape-paraglider-sucked-32-000ft-storm.html
Amazing escape of paraglider sucked 32,000ft into storm
Last updated at 21:12 16 February 2007
