Re: [Paddlewise] Water Motion Within a Wave (was: How a Kayak Turns)

From: Dave Kruger <kdruger_at_pacifier.com>
Date: Mon, 22 Jan 2007 18:38:36 -0800
Well, this topic has generated more uncertainty than I had expected.  Bob 
Myers and I have a discussion going on, back channel, in which each of us 
is hedging on which of the diagrams we each submitted might be "correct." 
I'll confess I'm at sea, so to speak.

However, I'm pretty certain of this:  Craig, watch that animation in your 
second link closely and you will see that the _motion_ of the blue dots 
does not correspond to what the _language_ in the first link says, if "As a 
wave arrives" is taken to mean "beginning with the trough," and "forward" 
is taken to mean "in the same direction as the wave is traveling."

In fact, the animation in the second link shows the water moving _back_, UP 
the face (like you said originally), until the crest arrives;  then the 
water moves _forward_ and down. (I took out the ":" so the link will come 
up without editing)

Craig wrote:

> Here is a quick quote from http://www.mos.org/oceans/motion/wind.html
> 
> 'As a wave arrives it lifts water particles. These travel forward,
> then down and back so that each particle completes a circle. "
> 
> Of course, there could be some confusion as to what constitutes the
> "face" of a wave and what is the "back". For me, the face is the
> frontside of a moving wave and the water particles are moving down
> that face. Even though the water rises, the particles in the water on
> the face of that wave are falling.

> Counter-intuitive, I know.

And, at odds with the animation in the second site [below], I believe.

> An excellent animation of various wave motions can be found at:
> http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html
> The animation of water waves (3rd animation down) clearly shows how
> the particles of water behave in a wave. 

-- 
Dave Kruger
Astoria, OR
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Received on Mon Jan 22 2007 - 18:39:18 PST

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