Subject: Re: V-formation flying (repost)
Date: Nov 2 10:34:19 1996
From: Jack Bowling - jcbowling at mindlink.bc.ca


(This is a repost of my seriously format-challenged earlier post. Hope this
one makes it OK).

Dennis stirring up the pot yet again...

> I was cleaning out my e-mailbox and found this; it's long, but I thought
> it might interest those of you who admire birds, as I do, in good part
> because of their flight. The "prevailing wisdom" is that birds fly in
> lines and vees to gain aerodynamic advantage (lift) from the air currents
> generated by the birds in front of them. I have long questioned this, my
> alternative being that the birds fly in formation so they don't run into
> each other! Smaller, more agile birds, fly in clumps, but when you get up
> to a certain size, lines and vees are the rule.
< and certain pertinent includes from the ORNITH-L list>

My comments on this are summed up thusly:
- the wake-vortex pattern shed from the back of a mobile-winged structure
such as that of a migrating goose's wing flying at 70 km/h would be
substantially different from that shed by a fixed-wing fighter trainer
flying at Mach 0.4, especially with regard to the initial magnitude of the
horizontal vorticity of the vortex itself, and the rate of deformation of
the vortex pattern by the ambient wind field. Likely apples and oranges
here.
- certain wing structures could quite likely create a wake-vortex
pattern which would help rather than hinder V-formation flying. Computer
simulations could help here. Please direct me to any applicable references.

I remain appreciative of Dennis's ceaseless questioning of old paradigms.
But I also remain acutely aware of nature's way of evolving just the right
way of doing things.

- Jack

Jack Bowling Prince George, BC Canada
jcbowling at mindlink.bc.ca


Jack Bowling
Prince George, BC
Canada
jcbowling at mindlink.bc.ca