Question

The discharge Q in a rectangular channel is 6m3 /s. The channel width is 3m and flow depth is 2m. (i) The channel width is reduced (no change to bed elevation) to 1.5m at a downstream location. What is the flow depth at the constriction? Determine if choking conditions are present. Explain your answer using of a q-y curve. (ii) The channel width is reduced (no change to bed elevation) to 1.0m at a downstream location. Calculate the upstream water rise. Explain your answer with the use of an E-y curve.

Answer 1

Given baa the channe! idth, &-3 m The Hew depy The Redvced Chamme dhlsm The flow depth at th Const히clfo",a=? Heye 3 ニスm , As bed depth don't change, 4

2 2 2 By asing (oail and o mehod vpstaean. 2 A 29 .3673 m

3673 95.007ms 5.0076 up stseam ho depthlnlchange and

A V94 x279x2 タ\ Upstream numbed = C-2254/ tfese 2 →\えー?.gm 2 šegion 2→ max and Iteoeforse dePh aedtoe as shown gonfhakeve

oe → So, the Upst seam flow gets destsiboted and deoonSoeamome clia 2 2 3 x.sy2 2 2.25m

de 20S 2.36 one a wish, vcec he Po l chock and Clntnt addtion gothe I SpedPrc eresa gets distibeted and demands adfol spedfre eney om 2.es m to . 313 17