Unformatted text preview: coefficient: v v Cd | Q/(by1) For a round-nosed broad-crested weir, Eq. (10.57) applies. For an unfinished cement surface,
2.4 mm from Table 10.1. Then the displacement thickness is
L | Ans. (a) e-Text Main Menu | 0.544 1 0.00994
0.6 m/1.2 m Textbook Table of Contents | 3/2 0.528 Study Guide 0.00994 692 Chapter 10 Open-Channel Flow
The estimated flow rate is thus
Q Cdb gH3/2 0.528(4 m) (9.81 m2/s)(0.6 m)3/2 3.07 m3/s Ans. (b) Check that H/L 0.5 0.7 as required. The approach Reynolds number is V1H/
2.9 E5, just
barely below the recommended limit in Eq. (10.57).
Since V1 0.5 m/s, V2/(2g) 0.012 m, so the error in taking total head equal to 0.6 m is
about 2 percent. We could correct this for upstream velocity head if desired. Other Thin-Plate Weir Designs Weirs are often used for flow measurement and control of artificial channels. The two
most common shapes are a rectangle and a V notch, as shown in Table 10.2. All should
be fully ventilated and not drowned.
Table 10.2a shows a full-wi...
View Full Document
This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.
- Spring '08