Maharashtra Engineering Civil Services Main Exam 2011 Civil Engineering Paper III

Q1. Define and briefly explain Newton's Law of Viscosity. Also differentiate between kinematic and dynamic viscosity. The surface tension of water in contact with air at 20^circC is given as 0.0716 N/m. The pressure inside a droplet of water is to be 0.0147 N/cm² greater than the outside pressure. Calculate the diameter of droplet of water. Explain the condition of equilibrium for a floating body and submerged body.

Q2.

• (a) Explain the phenomenon of capillarity and obtain an expression for capillary rise of a liquid. A rectangular tank 4 m long, 1.5 m wide contains water upto a height of 2 m. Calculate the force due to water pressure on the base of the tank. Also find the direction of this force and depth of centre of pressure from free surface.
• (b) Distinguish between following:
  (i) Uniform flow and non uniform flow Steady flow and unsteady flow
  (ii)
  (iii) Rotational flow and irrotational flow What are the limitations of Bernoulli's theorem? Water is flowing through a pipe having diameters cm and cm at sections 1 and 2 respectively. The discharge through the pipe is 0.04 cumec. The section 1 is 6 m above datum line and section 2 is 3 m above datum. If pressure at section 1 is 29.43 N/cm2, what is the pressure at section 2?
• (c) A rectangular channel carries water at the rate of 0.5 cumec when bed slope is 1 in 3000. Find the most economical dimension of the channel if C is 60.
• (d) List any three dimensionless numbers. Also explain their significances for fluid flow problems. Describe the working of reciprocating pump with a neat sketch. Draw a typical layout of hydroelectric power house and name the components. SECTION - B 10 3. Explain the terms infiltration and infiltration capacity. In a Hr storm rainfall (a) occurred over a catchment the rainfall depths are as given below : 2 3 9 4 6 7 Hours 1 5 10 1.5 5.0 6.0 10.5 8.5 9.0 7.0 1.5 Depth cm/hr 1.0 1.5 Surface runoff resulting from the storm is equivalent to cm of depth over the catchment. Determine the average infiltration and average rate of infiltration.

Q3. The surface tension of water in contact with air at 20^circC is given as 0.0716 N/m. The pressure inside a droplet of water is to be 0.0147 N/cm² greater than the outside pressure. Calculate the diameter of droplet of water.

Q4. Explain the condition of equilibrium for a floating body and submerged body.

Q5. The velocity vector in a fluid flow is given by, V = 2x³ i - 5x²y i + 4 tk. Find the velocity and acceleration of a fluid particle (1, 2, 3) at time t = 1.

Q6. What do you understand by most economical section of a channel. Also derive the conditions for rectangular channel of most economical section.

Q7. A syphon of diameter 150 mm connects two reservoirs having a difference in elevation of 15 m. The length of the syphon is 400 m and summit is 4 m above the water level in the upper reservoir. The length of the pipe from upper reservoir to summit is 80 m. Determine the discharge through syphon. Also determine the pressure at summit, consider coefficient of friction as 0.020 and neglect minor losses.

Q8. Describe the functions of main components of Pelton turbine with neat sketch.

Q9. Find the power required to drive a centrifugal pump which delivers 0. 04 cubic metre per second of water to a height of 20 m through a 15 cm diameter pipe and 100 m long. The overall efficiency of the pump is 70%. Consider coefficient of friction as 0.

Q10. Explain the phenomenon of capillarity and obtain an expression for capillary rise of a liquid.

Q11. A rectangular tank 4 m long, 1.5 m wide contains water upto a height of 2 m. Calculate the force due to water pressure on the base of the tank. Also find the direction of this force and depth of centre of pressure from free surface.

Q12. Distinguish between following:
(i) Uniform flow and non uniform flow
(ii) Steady flow and unsteady flow
(iii) Rotational flow and irrotational flow