Section A
Q1.
(a) If the velocity components for two dimensional flow are given by u = (x)/(x2 + y2) and v = (y)/(x2 + y2), determine the acceleration components in X and Y direction and rotation in Z direction at two points in the flow field (i) 2, 3 and (ii) 4, 5. Coordinates are in metres.
(b) What are the different forces acting in a moving fluid ? Also discuss different similarity model laws used to study the dynamic similarity of a prototype.
(c) A stream has a width of 25 m, depth of 2.5 m and mean velocity of 1.5 m/sec. Find the height of weir to be constructed on the stream floor to raise the water level by 1 m. Assume value of discharge coefficient as 0.95.
(d) Define 'noise' and explain as to why and how it should be regarded as an environmental pollutant. Also explain briefly the major factors and actions that may help in noise abatement in a modern society.
(e) A wastewater treatment plant discharges 1.0 \text m3/\textsec of effluent having an ultimate BOD of 45.0 mg/L into a river flowing at 10.0 m3/sec. Just upstream from the discharge point, the river water has an ultimate BOD of 4.0 mg/L. The deoxygenation constant (kd) is 0.22/day. Answer the following: (i) Assuming complete and instantaneous mixing, what would be the ultimate BOD of the mixture of waste and river just downstream from the outfall? Assuming a constant cross-sectional area for the river equal to (ii) 60 m2, what ultimate BOD would you expect to find at a point 10.0 km downstream?
