Hydraulic Tables, Coefficients, and Formulae for Finding the Discharge of Water from Orifices, Notches, Weirs, Pipes, and Rivers
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1875 edition. Excerpt: ...bank, to 45 feet at the level of the top of the weir, the average width at this place as the water rose being 55 feet. The channel above and below the slip widened to 80 and 123 feet. Between the mills and the weir there were, therefore, two passes; one at the slip, averaging 55 feet wide; another above the weir, about 120 feet wide. Assuming as above, that the water rises to the heights due to weirs 55 and 120 feet long, at these passes, then, by an easy calculation, or by means of Table X., the heads in columns two and four of the table on the next page were found, corresponding to the assumed ones on the weir, given in the first column. As the length of the river was short, and the hydraulic mean depth pretty large, the fall due to friction for 60 feet above the weir was very small, and therefore no allowance was made for it; even the distance to the slip was comparatively short, being less than half a mile, and as the water approached it with considerable velocity, this was conceived, as the observations afterwards showed, to be a sufficient compensation for the loss of head below by friction. The observations were made by a separate party, over whom the Author had no control, and it is necessary to remark, that with the same head of water on the weir, they often differed more from each other than from the calculation. This, probably, arose from the different directions of the wind, and the water rising during one observation, and falling during another. The true principle for determining the head at g, Fig. 89, apart from that due to fric tion, is that pointed out at pp. 186 and 141, but when the passes are very near each other, or the depth d2, Fig. 23, is small, the effect of the discharge through d2 is inconsiderable in reducing the head, ..
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- 01 Jun 2012
- Miami Fl, United States
- Illustrations, black and white