Last year I posted about Hat Creek in northern California, and in the process of creating the post, I came up with a number of links about hydraulic jumps. I was trying to teach myself a little about hydrology, which was not something taught in any class offered while I was in school many years ago (except for Ground Water Hydrology, which didn't get into the surface water or surface flow aspects of ground water very much). I became confused reading about hydraulic jumps online, about how the water level increases where the flow changes from supercritical to subcritical (in a downstream direction), with whitewater or rapids being examples of hydraulic jumps. My confusion came because in my pictures of Hat Creek, the water level starts off higher, then drops into the rapids after flowing over some logs. What I failed to realize until things were clarified for me by Anne Jefferson at Highly Allochthonous, was that my Hat Creek photos show a *small* hydraulic jump, and that the water level rises in the whitewater itself, nevermind the drop it makes over the log jam.
Rather than trying to explain hydraulic jumps further myself, I'm simply going to provide some links for those of you that want to learn more.
Critical flow constrains flow hydraulics in mobile-bed streams:
A new hypothesis (1997) Gordon E. Grant: Water Resources Research - A 1.2 MB pdf, possibly not that new anymore?
Hydraulic model study of a canoe chute for low-head dams in Illinois (1999) Marjorie E. Caisley, Fabian A. Bombardelli, and Marcelo H. Garcia: Illinois Department of Natural Resources - A 6.0 MB pdf, long and somewhat technical.
Hydraulic Jumps: Bubbles and Bores (2007) H. Chanson: 16th Australasian Fluid Mechanics Conference, Crown Plaza, Gold Coast, Australia - Technical, with good examples of tidal bores.
"The hydraulic jump is the sudden transition from a high-velocity open channel flow regime to a subcritical flow motion."Open Channel Flow Basics - Hydraulic Jump Calculations (2010) Harlan Bengtson: Bright Hub - Some basics with calculations.
"A hydraulic jump occurs wherever a supercritical flow is taking place in a channel that doesn't have a slope steep enough to maintain the supercritical flow."Hydraulic Jump (2003) Cathy Hartner, Shelly Davis, and Michon Hale - basics and some calculations (possibly a student paper?).
"A hydraulic jump is a sudden rise in water level due to decreasing velocity."Hydraulic Jumps I: 1-Layer Flow by Bruce R. Sutherland: University of Alberta - pictures of hydraulic jumps.
Surface Tension and the Hydraulic Jump by John W. M. Bush: MIT - More pictures!
Hydraulics over a weir by Little River Research and Design - A great video showing a hydraulic jump.
Underwater view of turbulence and fish by Little River Research and Design - An underwater video, I didn't see the fish, just the rocks. UPDATE: See first comment and additional video below.
Smallmouth bass and dusky shiners in high velocity closeup - Also by Little River Research and Design - this is the one with the fish in it!
(This post is part of my ongoing project to clean out my drafts folder, which I usually revive at the beginning of each year.)
4 comments:
Cool post! You found a mis-captioned video of mine, thanks (and sorry about lack of fish, see the very next video for that).
And thanks for the linkage.
Steve
Steve, the fish-turbulence video is very cool! When I watched the other one, I kept thinking I was just missing something. :)
I added the "fish" video.
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