Ok, after doing some more googling I am beginning to understand this added-mass business.
This file explains the effect using the motion of a weight immersed in a fluid hanging from spring. http://web.mit.edu/2.016/www/labs/L01_Added_Mass_050915.pdf Harry Harry Veeder wrote: > > > Consider this question and comment I added to the wiki page on added-mass. > > How does one determine how much of the surrounding mass to add? It sounds > like added-mass is an egineering fudge factor rather than good science. > > http://en.wikipedia.org/wiki/Added_mass > > Harry > > > Rick Monteverde wrote: > >> Use your hand to push a handful of air. Now imagine you have a vortex >> and push that with your hand. You're moving more air, more reaction >> mass. Isn't that what they mean in the article, or they just don't say >> at all? The vortex ties air together into a momentary 'thing' that has >> more mass than the smaller handful of air. I doubt the increase in >> reaction mass at insect reynolds numbers does much, but I guess it all >> adds up with rapid wing-beats. The viscous drag against the larger pulse >> of air moving through the surrounding air is a good thing too if you're >> pushing either down or backwards or both to get thrust and lift. >> Probably would work even better on a larger scale - like for human >> powered flight. Flonk... Flonk... flonk... >> >> -----Original Message----- >> From: Harry Veeder [mailto:[EMAIL PROTECTED] >> Sent: Wednesday, November 30, 2005 1:52 PM >> To: [email protected] >> Subject: Re: Secrets of bee flight revealed >> >> >> The article mentions the forces provided by the vortices...but the >> origin of the "added-mass force" is not explained. >> >> quote: >>> Lastly, there is another peculiar force known as >>> added-mass force which peaks at the ends of each stroke and is related >> >>> to acceleration as the wings direction changes. >> >> >> Harry >> >> Rick Monteverde wrote: >> >>> Conceptually that means more stuff to push off of. <???> >>> >>> These kinds of wings create vortices of air which feature increased >>> mass and resistance to downward/rearward movement than a similar >>> surface would encounter while slicing through the medium in a more >>> laminar mode. Probably get increased stability too. >>> >> >> >> >> >> >
