Calculating shear in Channels?
Calculating shear in Channels?
(OP)
The typical formula used to calculate shear in a channel bottom is:
62.4 * Depth * slope in ft/ft = Shear in PSF
This is listed in Hec 15, Design of Channels with Flexible Liners.
Is this just an empirical formula? I don't see what slope has to do with shear in a channel, mathematically speaking.
I could see figuring the downward component of the gravity acting on the water to determine shear, but not raw slope.
62.4 * Depth * slope in ft/ft = Shear in PSF
This is listed in Hec 15, Design of Channels with Flexible Liners.
Is this just an empirical formula? I don't see what slope has to do with shear in a channel, mathematically speaking.
I could see figuring the downward component of the gravity acting on the water to determine shear, but not raw slope.





RE: Calculating shear in Channels?
t = wRS
Where: t = tractive force, or shear force
w = weight of water (62.4)
R = hydraulic radius
S = channel slope
Chow also explains that, except in wide channels, the tractive force is not uniformly distributed along the wetted perimeter.
RE: Calculating shear in Channels?
RE: Calculating shear in Channels?
I wish I had a copy of Chow, but the $300 price of admission is a deterrant.
RE: Calculating shear in Channels?
Try www.gettextbooks.com I found a soft cover international edition for about $50 a couple of years ago. Listed at about $65 now, but its one of the best references I own.