GATE 2018 CE (CE1) – Question 60
A hydraulic-structure model has discharge 0.05 m³/s and velocity 0.25 m/s. The full-scale structure is 30 times larger and carries 270 m³/s. Model-to-full-scale time ratio, to two decimals, is ______.
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Correct answer: 0.15 to 0.25
Explanation
Prototype/model area ratio is $30^2=900$ and discharge ratio $270/0.05=5400$. Continuity gives velocity ratio $5400/900=6$. Time ratio is length ratio divided by velocity ratio: $T_p/T_m=30/6=5$. Requested model/prototype ratio is 0.20.