Talk:Saltation (geology)

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Saltation: 1-a geophysics process(+biology); 2-a concept

The orginal Saltation article was focussed on fluid transport in the field of Fluid dynamics-(stream flow). My original meeting with saltation was in sand-dune, and sand, (but see also loess), and later I saw the process used in analyzing river bottom movements of the "River load", the transport of particles downstream (which can end up: upstream in eddies, etc.)-

However, I still contend the "process" of saltation is a more important concept when used with time and the "rate-of-change" that occurs. To pick a geoligic time: "hundreds of years" or "thousands of years", is a statement that is 'unknowable'. I would assume with the speciation, and the overabundance of off-spring, -(the conclusion has to be): "Generations are Shortened!"--under some environmental conditions, I would err on the side, of more rapid 'Geologically-bsed' changes, as opposed to the extended: "thousands of years"; it may apply to some mammals, but I think the time frames, have to be shortened..[And....I do think this goes towards understanding the positions taken on the Punctuated equilibrium discussion-](I think some species come along so fast, one doesn't see them coming..) ... Just some thoughts--at... "part-of-1-year" after the original article was split. //--From the Arizona-Desert--Mmcannis 20:50, 19 November 2006 (UTC)[reply]

fluid dynamics

I added much of the original content on this page. FWIW, fluid dynamics is not the same as stream flow. The expression fluid dynamics refers to the dynamics of a fluid in an engineering sense, where air is as much a fluid as water.

Anyway, is it worth starting a page on transport of particles by fluids? —Preceding unsigned comment added by 142.207.115.25 (talk) 21:09, 25 February 2008 (UTC)[reply]

I think it would be good to rename the title of the article, because the mechanism of saltation in fluid dynamics is just the same.--Graham Proud (talk) 05:57, 29 September 2012 (UTC)[reply]

Parabolic trajectory

A parabolic trajectory could not possibly be a defining characteristic. Particles only move in parabolic arcs when they are in a vacuum, NOT in a fluid. There might be something close to parabolic when the saltation occurs at low velocities, and I'm sure the math is interesting, based on the vector, velocity and viscosity of the fluid, and the mass and size of the particle. Maybe even the coefficient of friction on the surface of the particle. But sand particles in a sandstorm fly in a very complex motion, going up and down depending on which way the wind blows. The particles shown in the wind-tunnel photo at the bottom of the main page are not traveling in parabolic arcs, either. So I'm deleting that phrase.

I am also disturbed by the explanation of the physics in the third paragraph. Some of it is clearly true, but some is suspicious. I'm going to watch this page to see if anyone can clean it up.

--cbdorsett (talk) 03:43, 2 August 2011 (UTC)[reply]

I agree that the physics in the third (and fourth) paragraph was incorrect, and I've tried to fix it. Also, the particles move in approximately ballistic trajectories, indeed not parabolic.

--Jfk nl80 (talk) 22:53, 4 April 2014 (UTC)[reply]

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