Arow of rectangular baffle blocks (0.4m high, 0.6m wide and 1.0m long) are to be installed in a 12m wide stilling basin to aid energy dissipation after a dam spillway. the blocks are spaced uniformly 0.4m apart across the spillway exit. the drag force d in each block is given by d = 0.5cd\small \rhov 2afb, with afb as the frontal area of the block and cd as the effective drag coefficient = 0.25 and v as the upstream velocity. if the flow rate is 150m3 /s and the upstream depth is 2m, determine the downstream water depth and energy loss for the two cases;

(a) blocks not installed (energy dissipated as a hydraulic jump downstream)

(b) blocks installed (momentum theory, considering drag forces)

(c) summarize a comparison between both scenarios