Jawaharlal Nehru Technological University Hyderabad B.Tech II Year FLUID MECHANICS AND HYDRAULIC MACHINES Previous Question Paper (April/May - 2018 - R16)

Distinguish between cohesion and adhesion.

Explain atmospheric, gauge and vacuum pressures.

Differentiate between surface and body forces.

Explain the applications of Bernoulli’s and Momentum equation.

Define boundary layer.

Describe HGL and TEL.

Explain how energy transformation takes place in turbines.

What is meant by geometric similarity?

Explain the principle of centrifugal pumps.

What is specific speed? What is the significance of it?

What is the difference between U-tube differential manometers and inverted U-tube differential manometers. Where are they used?

An open tank contains water up to a depth of 1.5 m and above it an oil of sp.gr.0.8 for a depth of 2 m. Find the pressure intensity: (i) at the interface of the two liquids, and (ii) at the bottom of the tank.

What is Viscosity? What is its significance in flow problems? What is Newton’s law of viscosity?

A cubical block weighing 20 kg and having a 20 cm edge is allowed to slide down on an inclined plane surface making an angle of 20° with the horizontal on which there is a thin film having a viscosity of 0.22 × 10^-3 kg-sec/m^2. What terminal velocity will be attained if the film thickness is estimated to be 0.025 mm?

Integrate three-dimensional Euler’s equations for steady flow condition and prove that each one of them yields Bernoulli’s equation.

A pipe of diameter 200 mm. conveys a discharge of 2250 lit of water per minute and has a pressure of 15.70 kPa. at a certain section. Find the total energy head with respect to a datum of 5 m. below the pipe.

Define stream line, path line and streak line. Derive mathematical expressions for each of these lines.

A 75 cm diameter uniform pipe bend turns the directions of flow of gasoline of sp.gr. 0.79 through an angle of 120° in the horizontal plane. The constant pressure and velocity through the bend are 90 kPa and 3 m/s respectively. Find the magnitude and direction of the force to be exerted on the bend to achieve the directional change.

Derive an expression for the loss of head due to friction in pipes.

The water is flowing through a pipe of diameter 30 cm. The pipe is inclined and a venturimeter is inserted in the pipe. The diameter of venturimeter at throat is 15 cm. The difference of pressure between the inlet and throat of the venturimeter is measured by a liquid of specific gravity 0.8 in an inverted U tube which gives a reading of 40 cm. The loss of head between the inlet and throat is 0.3 times the kinetic head of the pipe. Find the discharge.

What conditions should be satisfied for separation of boundary layer? Discuss briefly the methods that can be used to prevent separation.

How will you determine whether a boundary layer flow is attached flow or detached flow or on the verge of separation?

Explain how the performance of a turbine is evaluated with the help of characteristic curves.

Describe the theory and functions of draft tube.

A jet has a direct impact on a plate moving in the direction of the jet. Find the force of impact and the work done by the jet per second on the plate. Can this case occur in practical cases? Explain.

A jet with a velocity V strikes a single curved vane moving in the same direction as the jet with a velocity u. The velocity of the vane is (V – u). The vane causes the flow direction to be completely reversed. Show that V = 3u for maximum efficiency. Determine this maximum efficiency.

How will you determine the possibility of cavitation to occur in the installation of a pump.

What are pump troubles and remedies? Explain.

What is the difference between single-stage and multistage pumps. Describe multistage pump with (i) impellers in parallel, and (ii) impellers in series.

Find the number of pumps required to take water from a deep well under a total head of 160 m. Also the pumps are identical and are running at 1100 r.p.m. The specific speed of each pump is given as 22 while the rated capacity of each pump is 155litre/s.