Question Paper: Fluid Mechanics : Question Paper Jun 2014 - Mechanical Engineering (Semester 3) | Visveswaraya Technological University (VTU)
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## Fluid Mechanics - Jun 2014

### Mechanical Engg. (Semester 3)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
1 (a) Give reasons:
i) Dynamic viscosity of gases varies with temperature.
ii) Cavitation must be avided in most of the flow systems.
(4 marks)
1 (b) Derive the relation for pressure intensity and the surface tension, in case of soap bubble.(4 marks) 1 (c) Determine the density and mass of air in a room whose dimensions are 4m × sm× 6m at 100kPa and 25°C. Take R=287J/kg K.(4 marks) 1 (d) The viscosity of the fluid to be measured by a viscometer constructed of two 75cm long concentric cylinders. The outer diameter of the inner cylinder is 15cm, and the gap between the two cylinder is 1mm. The inner cylinder is rotated at 300rpm, and torque is measured to be 0.8 N-m. Determine the viscosity of the fluid.(8 marks) 2 (a) Differentiate between absolute, gauge and vacum pressure. Represent these pressures on a chart(4 marks) 2 (b) Derive the expression for total pressure force and depth of center of pressure for a vertical plane surface submerged in liquid.(10 marks) 2 (c) A differential manometer is connected at the two points A and B of two pipes as shown in the fig Q2(c). The pipe A contains a liquid of Ap. Gravity=1.5 while pipe B contains a liquid of specific gravity=0.9. the pressure at A and B are 9.81N/cm2 and 17.66 N/cm2> respectively. Find the difference in mercury level in the differential manometer. Take sp. Gravity of mercury=13.6
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(6 marks)
3 (a) Differentiate between