Yup in space !
No pressure ,no resistance = increased speed.
BTW…HE’S AN EXCEPTION…and my hero.
Of course I was talking about… WITHIN the stratosphere…HERE.
Even Halo drops at 30,000 ft…that’s 6 miles up…the speed increases until you hit about 20,000 or so.
H
Your ‘‘progression of wave’’ arrow is pointing in the wrong direction, to be in agreement with your diagram.
Hi doc,
Interesting analysis. Could you tell me, if the water is not moving up the face then how does it get there?
I think that you are right that gravity is the main force involved in most situations, but as the waves gets bigger and steeper water flow becomes more of a factor.
Also, I think that a wave breaks forward because as the wave approaches the shore the trough slows down and the crest continues at the (faster) momentum that it had. So the crest breaks on top of the trough.
If you think about it, super throwing barrels like Teahupoo or Pipe (extreme examples). the swell is approaching the beach real fast and all of a sudden the bottom contour changes dramatically (shelf) and the trough of the wave puts on the breaks while the crest continues at the original speed of travel. As the crest continues to move at the original speed it pulls lots of the water (water has viscosity and is sticky like silly putty, but not so extreme) from the trough up the wave face.
So I think for super small waves the forward motion of the wave is a relatively larger factor. As the waves get bigger gravity starts to come more into play. And as the wave gets bigger and steeper water flow has more a factor.
Hi Steve;
While I wasn’t able to figure out how to see said contest live, I’ll stand by the statement. The waves we ride are not always breaking…just that moment, not 'til we are in that spot where the lip is starting to arc out overhead, where I’ll grant that some upward flow is going on.
But…lets see what’s happening here.
You have a deep ocean swell coming out of nowhere and suddenly thwacking into this really shallow reef, which is right about at sea level.
But…you got open ocean waves…and troughs. Which are hitting that reef pretty much in open ocean form. Now, could the water draining towards the wave and giving the appearance of being sucked in - could that be the water draining away into the trough?
Just my look at it…
doc…
not sure what you mean but I dig the Goldfish hanging in the channel.
Drag, anyway.
Wait! I don’t wanna get left behind–gravity isn’t a dominant factor on small waves or big huge waves, right?
That’s a great explo, and you are right.
There are forces at work in surfing ,allright- dark forces…
They want to tell us how a wave should be ridden
They want us to want to ride waves the way they think we should
On equipment That they want to sell us
They want us to wear their clothes
To buy their image, pursue their vision for us - not our own
Long live the Revolution.
; )
Oh that’s with 80 to 120 lbs. of cr#p strapped to your body,of course.
H
Holy Guacamole Herb! You sky-surfed a royboard???
LOL!!
use the force…
Hi ob,
Lets see if I can get my thoughts back around this, after a good night’s sleep and a cup of coffee;
First off, I’m making a distinction between waterflow and water staying put relative to shore as a wave goes by. Unfortunately, I’m pretty much useless with animated GIFs and the like, so I’ll have to settle for a few mediocre sketches.
Lets consider the wave itself moving along, unbroken. It’s a lot like, say, a pipe being rolled along under a sheet. When it starts to drag on the bottom, it picks up, but that rotary, rolling motion continues.
And…a good illustration here: http://highered.mcgraw-hill.com/sites/0072826967/student_view0/chapter20/animations_and_movies.html# see Fig. 20.4, orbital motion in shallow water
Good thing too, as I couldn’t find my copy of Bascom’s Waves and Beaches and I’m going as much from memory as anything else.
Now, as the wave approaches the shore, yes, the trough does slow down. But so does the peak: the wavelength decreases. And the peak height goes up, but the circular wave form still is acting. And throwing out, etc. Gravity is a mighty strong force, relatively speaking, such that a simple surge wouldn’t go concave and throw out; wave speed, especially slowed down by drag on the bottom, isn’t enough to make that lip come over to the extent that it does…it’d just collapse down the face. Water viscocity isn’t nearly strong enough to hold it together like that.
Okay - that’s a regular ocean swell wave, travelling at less than say, 50 MPH. There’s another kind of wave that does act as you describe. Tsunamis, which are travelling at around 10 times the speed of your basic ocean swell, with a really, really long wavelength, when they hit they do trip up, as you describe, and surge. In some conditions the bottom drag holds back the lower part of the surge and you basicly get a big roller coming in - http://www.youtube.com/watch?v=C4lpIaSraPE&feature=related is an illustration, if that link works…
Anyhow, hate to make this short, but I gotta go get a tooth put back in. Yesterday was One of Those Days-
doc…
LOL. It must have been a slow board. if it were a roy board it would break the sound barrier regardless of the atmosphere.
NOW THAT’S FUNNY !
I got pushed out of planes or choppers regularly w/a medic pak,an Model 700 Remington in 7mm magnum w/a 4 x12 x 50wo scope,FN-FAL w/a 10 x 50wo scope, or whatever I wanted to use as my tool ,and as much heat to do the job as I needed.I have over 100 confirmed and have 100% completion ratio.
I still to this day talk by phone to the techs over at Remington in NY or NC…Great group of guys,very helpful and appreciate my input.
I’m a Hunter first and foremost in my life.
H
First off, I’m making a distinction between waterflow and water staying put relative to shore as a wave goes by. Unfortunately, I’m pretty much useless with animated GIFs and the like, so I’ll have to settle for a few mediocre sketches.
Lets consider the wave itself moving along, unbroken. It’s a lot like, say, a pipe being rolled along under a sheet. When it starts to drag on the bottom, it picks up, but that rotary, rolling motion continues.
And…a good illustration here: http://highered.mcgraw-hill.com/…ions_and_movies.html# see Fig. 20.4, orbital motion in shallow water
Doc, I think that you are right that the water stays relatively in the same place with respect to shore, but the water on the face does move up toward the sky, and even away from the beach a little as the wave energy moves toward the shore. The illustration you linked to clearly shows that.
Now, as the wave approaches the shore, yes, the trough does slow down. But so does the peak: the wavelength decreases. And the peak height goes up, but the circular wave form still is acting. And throwing out, etc. Gravity is a mighty strong force, relatively speaking, such that a simple surge wouldn’t go concave and throw out; wave speed, especially slowed down by drag on the bottom, isn’t enough to make that lip come over to the extent that it does…it’d just collapse down the face. Water viscocity isn’t nearly strong enough to hold it together like that.
You are right that the peak also slows down, but the trough slows down more relative to the peak.
As to how the wave breaks, most waves do just collapse down the face. It is only in the certain special situations where the trough is slowed down super fast that the crest throws over and barrels.
Okay - that’s a regular ocean swell wave, travelling at less than say, 50 MPH. There’s another kind of wave that does act as you describe. Tsunamis, which are travelling at around 10 times the speed of your basic ocean swell, with a really, really long wavelength, when they hit they do trip up, as you describe, and surge. In some conditions the bottom drag holds back the lower part of the surge and you basicly get a big roller coming in - http://www.youtube.com/…&feature=related is an illustration, if that link works…
Anyhow, hate to make this short, but I gotta go get a tooth put back in. Yesterday was One of Those Days-
doc…
If normal waves don’t break because the trough is slowing down faster than the crest, then what is your theory on why they break the way they do.
Hope your tooth gets better, dem things can hurt!
“Uhh oh…” Hahahhahahaha!!! What?!?
Thinking I was over this issue, but reading about it anyway, I thought of a good example: I think many would agree “the wedge” at the end of Newport Beach CA is an example of an extreme wave, and if so, I’ve surfed and body surfed out there on overhead + days, and I did not find myself being accelerated up the face in any extreme way, even thought the peak was sucking off the shallow sand bar. Maybe not the greatest example, but I’m still in the camp of; the water moving up the face is not large factor compared to gravity in relationship to friction and lift dependent on the AOA of the board and fins.
Sorry, couldn’t resist. I still need to consult with Bill T. re. what he knows, as I’m well aware my knowledge is limited.
(Sigh) I should’nt do this,I shouldn’t do this, I shouldn’t…
Let me evoke Einstein into the equation; everything is relative. To a bobbing duck, or boat or flotsam (or is it jetsom) there may be no flow up the face of a wave. But to a surfboard (and rider) paddling to catch a wave, something in excess of paddle power is causing the board to achieve enough velocity to allow you to abandon bouyancy and drop in using planing forces only. What is doing that?
In a trim, where the board is neither being paddled nor is it falling (due to gravity), the board is still planing. What is keeping the board planing?
Before you jump to answer these two questions, remember that your perspective is that of the bottom of a surfboard.
Come on in Lee, the water is fine… and may or may not be flowing in a significantly meaningful way… Ha!
Gravity.
The forces due to pressure differences.
TaylorO
I think I might have dipped below the event horizon…
“Gravity.”
In trim?!?
“The forces due to pressure differences.”
Occam’s Razor.
Let me digress a bit. If you are a surfboard bottom and you are being paddled over the water, which way is the water flowing?
If you are standing on the beach watching that same surfboard bottom being paddled over the water, which way is the water flowing?