Although the experimental work and analysis were performed
by Shields, the curve termed the Shields Curve,
which is shown in Figure 9-1, was actually proposed by
Rouse (ASCE 1975). Shields curve may be expressed as
an equation, which is useful for computer programming.
I'm sure there was probably some obscure notation of Rouse in one of my textbooks, but I must have overlooked it or this would not have been a bit of a surprise to me. I looked up Rouse and discovered that he, in fact, was given little to no credit for his work. When Rouse introduced the Shields diagram, he did so with auxillary parameters. You can read more on this here.
Further into the manual there is a section on Bank or Wall Shear Stress. Brownlie's approach appears to be the favored method, and the section is fairly well written describing the resistance equations and range of conditions. Duboy's concept where the significant assumption being that sediment
transport could be calculated using average cross-section
[hydraulic] parameters and that the main result of excess shear stress was transport of said sediment. (EM 1110-2-4000). There are a few more equations in this section, some of while were derived from Einstein, which I found interesting. Mostly because when I think of Einstein, I associate him with theoretical physics.
transport could be calculated using average cross-section
[hydraulic] parameters and that the main result of excess shear stress was transport of said sediment. (EM 1110-2-4000). There are a few more equations in this section, some of while were derived from Einstein, which I found interesting. Mostly because when I think of Einstein, I associate him with theoretical physics.
I was curious as to what other methods were implemented in calculating shear stresses in banks or walls, so I did yet another internet search. This one yielded quite a bit of interesting reading material. One of which was a paper pretty much dedicated to hydraulic shear stresses, with several different environments/situations outlined and the correlating equations: Shear Stress in Bends
Flow around bends creates secondary currents that exert higher shear forces on the channel bed
and banks than those found in straight sections. Several techniques are available for estimating
shear stress in bends. A relatively simple and widely used method, presented by U. S. Department of Transportation,2 estimates maximum shear stress on channel banks and bed occurring within bends. This equation, however, does not differentiate between bank and bed shear stress. The maximum bed/bank shear stress is primarily focused on the bank and bed on the outside portion of the bend .
Lastly was a link to a book on google books. This book, Introduction to bed, bank, and shore protection- by Gerrit J. Schiereck is by far the best [mathematically-heavy] book I have ever read. While I did not read the entire book, what I did read was so well written I forgot for a moment I was reading about math. In general, I like math, but it can be a love/hate relationship for me. I don't like to have to figure out what a writer is blundering through in addition to understanding the formulas. With this book you don't have to do that. The man is an artist, truly. When you can become so absorbed in what you are reading because they have grabbed your attention AND know how to write eloquently- well that is a book you just have to buy. So I did! You can catch a B&N link to it here, but it appears I bought the last copy. (At least I hope that is the case- my order went through, but you never know. I'll have to check my email when I finish up with this). The figure (Fig. 3.1, forces on a grain flow) at the beginning of this post comes from a section of his book.
On page 52 of the google book Schiereck describes Shield's formula for uniform flow, and how it isn't always the best choice. He explains why using shear stress as the active force this isn't always the best choice. On p. 65 he goes in to describe another environment (a dam or a groyne ) where you can use Shields eq. in conjunction with a slope correction. If you have time, read p. 72-73, as the part about geotextiles particularly is interesting.
Sources:
Introduction to bed, bank, and shore protection- by Gerrit J. Schiereck
Shear Stress in Bends
USACE EM 1110-2-4000
Rouse and Shield
.
Introduction to bed, bank, and shore protection- by Gerrit J. Schiereck
Shear Stress in Bends
USACE EM 1110-2-4000
Rouse and Shield
.
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