© R3924 Pages: 2
6 93) A venturimeter 30 cm x 10 cm is provided in a vertical pipeline to measure the (10)
flow of oil of relative density 0.85. The difference in elevations of the throat

section and entrance section is 40 cm, the direction of flow of oil being

vertically upwards. The oil-mercury differential U tube manometer shows a

gauge deflection of 20 cm. Calculate the discharge of oil and the pressure

difference between the entrance section and throat section. Take the coefficient

of discharge as 0.97 and specific gravity of mercury as 13.6. b) Define coefficient of velocity, coefficient
of contraction and coefficient of (5)

discharge. Find out the relation among the three.

PART C
Answer any two full questions, each carries 20 marks.

7 9) Derive the Hagen —Poiseulle equation for laminar flow in circular pipes. (10) b) A
horizontal pipe carrying water suddenly increases its diameter from 10 cm to (6) 20cm. Find
out the loss of head due to sudden increase in diameter if the discharge through the pipe is
150 litres/s. Also find out the pressure difference between the two sections.

c) Define Hydraulic Grade Line and Total Energy Line. (4)

8 9) The velocity distribution in the boundary layer is given by: = ರ್ಕ 3 1 = 3 (10)

where v is the velocity at a distance $ from the plate, y 4 and v = ۷ aty =6, 0
being the boundary layer thickness. Find the displacement thickness and the
momentum thickness in terms of 6

b) Differentiate between friction drag and pressure drag (4)

c) Whatare the factors affecting the boundary layer thickness along a flat plate? (6)

9 ‏رو‎ ^ 0.3 m diameter pipe 2340 m long is connected with a reservoir whose surface (10) is 72
m above the discharging end of the pipe. If for the last 1170 m, a second pipe of the same
diameter is laid beside the first and connected to it, what would be the increase in discharge?
Neglect minor losses. Take f=0.02.

b) Oil of specific gravity 0.85 and viscosity 2.5 Poise is flowing through a 30cm (10)
diameter pipe kept horizontally. The length of pipe is 2.5 km and the head loss
is 20 m. If the flow is laminar, estimate (i) shear stress at the pipe wall (ii) shear
stress at a radial distance of 10 cm from the pipe axis and (iii) the friction factor
f.

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