Question

SPILLWAY CHUTE er at 9.000 cfs is flowing in the spillway chute shown in Fig. P6.7.12 (a). The chute le rectangular in section having a width of 90 ft. The material is concrete with a smooth finish. A. Determine the depth of flow di, at the bottom of the 5% slope, assuming the 5% slope is very long. B. Determine critical depth in the rectangular cross section. C. Is the flow on the 5% slope sub-critical (tranquil flow) or super-critical (shooting flow)? Explain. D. Determine the required depth of tail water da, at Section 2 to cause hydraulic jump to form on the flat slope. - - - - CDL Flow - ---- S - 5% M3 Curve de 6.75 S - Ox L (2) Fig. P6.7.12 (a)

Answer 1

solution: Manning's for Roughness coeff. concrete channel n): 0.013 Discharge (Q) = 2496R+3) SV A ... 9000 = 149 23 (5100)" A 0.013 > A = 351:17 → (RMS) A 35117 med den lod33 243 Bid, Bdi = 351.17 B+ 2d, / B.d.) 5 2 = 4330 55 71.42 (B+ 2014 LB-90ft (a,j5 -0.007334 (90 + 2d, )2 = solue by hit and trial, ld, = 2.31 ft | ANS 10) de = ( 919 1920 = go = 100 48% 1.4 . do = (102) ** = 6.77 JANS

di = 2:31 ft @ 9ooo 9000 = 43.29 ft/s 1. Fraude | Fa No. Fale (su) 43.29 V32.2 x2:3) Fn = 5:02 > 1 (hence flow is super-critical) *(-* Vi+84502]