Mar. 6,1916 
Flow through Weir Notches 
1067 
Table; II .—Discharges (in cubic feet per second) through rectangular weir notches-*- Con. 
Head. 
Feet . 
I. 25 
I. 26 
I. 27 
I. 28 
I. 29 
Inches , 
IS 
15^ 
15X 
15^ 
1.30 
i-31 
1.32 
i- 33 
i. 34 
15^ 
isrt 
16* 
1*35 
1. 36 
i *37 
1. 38 
i *39 
1 
16-& 
i6* 
163% 
i6« 
1.40 
1. 41 
1.42 
1-43 
1.44 
16H 
16H 
17A 
17 A 
17X 
1. 45 
1. 46 
1. 47 
1. 48 
1.49 
i- 50 
17M 
17K 
17H 
17K 
17^ 
18 
i-foot crest. 
iK-foot crest. 
2-foot crest. 
6.43 
8. 66 
* 
; crest. 
4-foot crest. 
13 * 14 
17. 66 
13 * 30 
17.87 
13*45 
18. 07 
13.61 
18.28 
13 * 77 
18. 50 
T 3 * 93 
18. 71 
14 - 09 
18. 92 
14. 24 
19 * 13 
14.40 
19 * 34 
14. 56 
19 * 55 
14. 72 
19. 77 
14. 88 
19.98 
15.04 
20. 20 
15. 20 
20. 42 
15*36 
20. 64 
IS* 53 
20. 86 
15. 69 
21. 08 
15. as 
21.30 
16. 02 
21. 52 
16.19 
21. 74 
16.34 
21. 96 
16.51 
22.18 
16.68 
22. 41 
16.85 
22. 63 
17. 01 
22.85 
17.18 
23. 08 
The discharges through a notch having a crest length of 0.5 foot did not 
follow the same law as those through larger notches. This was probably 
owing to the greater effect of friction in the smaller notch and to the inter¬ 
ference due to the end-contraction filaments of flow crossing each other 
in the middle of the notch section. The formula 
was found to give discharge values consistent with the curve plotted from 
experimental data for the 0.5-foot notch. The use of such a notch is 
very limited, and the 90° triangular notch is as accurate and much more 
satisfactory. 
Comparison op the Francis Formula and the New Formula 
The discharge values obtained for rectangular notches by the Francis 
and the new formulas are shown in graphic form in figure 7 and in tabular 
form in Table III. 
27465°—16 - 2 
