# JNTU Question Papers

## Mechanics of Fluids I-Sem Nov 2008

1. (a) Define compressibility and bulk modulus of elasticity. Obtain an expression

for the bulk modulus of elasticity K of a fluid in terms of the pressure p and

the mass density.

(b) Determine the pressure increase required to reduce the volume of water by

1.5%, if its bulk modulus of elasticity is 2.2 X 109 Pa. [8+8]

2. (a) Define equipotential line and a line of constant stream function, Show that

these lines intersect orthogonally.

(b) Given that u = x2-y2 and v = – 2xy. Check whether stream function exists.

If so determine the stream function and potential function for the flow. [8+8]

3. (a) What is momentum equation? Give applications of the equation.

(b) Water under a pressure of 345 kN /m2 is flowing through a 30 cm diameter

pipe at the rate of 0.25 m3 / s. If the pipe is bent by 1350 to the horizontal, find the magnitude and direction of the resultant force on the bend. Neglect losses. [8+8]

4. (a) Define coefficients of drag and lift and state factors affecting on which those

coefficients depend.

(b) A kite has an effective area of0.4m2 and weighs 2.0 N in a wind of 40 km/hr.,

the drag on the kite is 12 N. Determine the tension in chord if the chord make an angle of45o with the horizontal. Also determine lift coefficient [8+8].

5. (a) What is the function of wind tunnel?

(b) What is meant by stagnation point. Explain [8+8]

6. (a) Explain Reynolds number and its significance in detail? What is the signifi-

cance of upper and lower critical Reynolds numbers.

(b) A viscous fluid of viscosity 2.2 poise and specific gravity 1.4 flows through a

40 cm diameter pipe. If the loss of head is 3 m in 100 m length, determine the shear stress at the wall pipe and velocity of flow assuming the flow to be laminar. [8+8]

7. (a) Give a graph of variation of friction head loss through a pipe against average

velocity. Explain the terms upper and lower critical velocities.

(b) Two pipes one of 10cm diameter, 200m long and another of 15cm diameter,

400m long are connected in parallel. The friction factors are 0.0075 for the

smaller pipe and 0.006 for the large pipe. The total discharge through the

system is 50lit/sec. Find the discharge and head loss in each pipe. Neglect

minor losses. Calculate the equivalent length of a 20cm diameter pipe having

f= 0.005. [8+8]

8. (a) What is Manometry. Explain with a neat sketch the working of single column

vertical Manometer.

(b) Explain how you use U-tube manometer to find pressure difference between

two points in fluid flow. [8+8]