| ω1/ω = | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 |
| ce = | .624 | .632 | .643 | .659 | .681 | .712 | .755 | .813 | .892 | 1.00 |
| ξc = | 225.9 | 47.77 | 30.83 | 7.801 | 1.753 | 1.796 | .797 | .290 | .060 | .000 |
Elbows.—Weisbach considers the loss of head at elbows (fig. 91) to be due to a contraction formed by the stream. From experiments with a pipe 11⁄4 in. diameter, he found the loss of head
ɧe = ζεv2 / 2g;
(5)
ζe = 0.9457 sin2 1⁄2φ + 2.047 sin4 1⁄2φ.
| φ = | 20° | 40° | 60° | 80° | 90° | 100° | 110° | 120° | 130° | 140° |
| ζε = | 0.046 | 0.139 | 0.364 | 0.740 | 0.984 | 1.260 | 1.556 | 1.861 | 2.158 | 2.431 |
Hence at a right-angled elbow the whole head due to the velocity very nearly is lost.
| Fig. 91. |
| Fig. 92. |