Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 4th Sem 3141906 Fluid Mechanics And Hydraulics Machines Previous Question Paper
Seat No.: ________
Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER? IV EXAMINATION ? SUMMER 2020
Subject Code: 3141906 Date:27/10/2020
Subject Name: Fluid Mechanics and Hydraulics Machines
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Marks
Q.1 (a) Explain hypothesis of continuum.
03
(b) State and prove Pascal's law.
04
(c) Derive Euler's equation of motion. State assumptions made. How
07
will you obtain Bernoulli's equation from Euler's equation?
Q.2 (a) How repeating variables selected for dimensionless analysis?
03
(b) With neat sketch explain the conditions of equilibrium for floating
04
body.
(c) Define uniform flow. Obtain stream and velocity potential function
07
when flow is parallel to x-axis. Also plot uniform flow (parallel to x
axis).
OR
(c) Derive from first principles, the conditions for ir-rotational flow.
07
Prove that for potential flow, both the stream function and velocity
potential function satisfy the Laplace equation.
Q.3 (a) Differentiate between stream and streak line.
03
(b) Define centre of pressure. Obtain expression for centre of pressure
04
for vertical plane surface submerged in liquid.
(c) The water is flowing through a taper pipe of length 100 m having
07
diameters 600 mm at the upper end and 300 mm at the lower end, at
the rate of 50 lps. The pipe has slope of 1 in 30. Find the pressure at
the lower end if pressure at the higher level is 19.62 N/cm2.
OR
Q.3 (a) The strea
03
m function for two dimensional flow is given by = 2xy.
Find velocity potential function .
(b) Define and explain the terms: HGL, TEL
04
(c) State Buckingham's ? theorem. The efficiency of a fan depends
07
on density , dynamic viscosity of the fluid, angular velocity ,
diameter D of the rotor and discharge Q. Express in terms of
dimensionless parameters.
Q.4 (a) Derive the expression of force in x and y direction when jet striking
03
symmetrical curved vane tangentially at one tip and leaving other
end.
(b) Prove that maximum velocity in a circular pipe for viscous flow is
04
equal to two times the average velocity of flow.
(c) Derive Darcy ? Weisbach equation.
07
1
OR
Q.4 (a) Define priming. Why priming is necessary in centrifugal pump?
03
(b) Classify hydraulic turbines with examples based on following
04
criteria:
i. Energy at inlet
ii. Direction of flow through runner
iii. Head at the inlet of turbine
iv. Specific speed of turbine
(c) A Pelton wheel is to be designed for the following specifications:
07
Shaft power = 11.772 kW, Head = 380 m, Speed = 750 rpm, Overall
efficiency = 86%, Jet diameter is not to exceed one-sixth of the
wheel diameter. Determine:
i. The wheel diameter
ii. The number of jets required
iii. Diameter of the jet.
iv.
Q.5 (a) Explain the advantages of Kaplan turbine over Fransis turbine.
03
(b) Define cavitation. State necessary precautions against cavitation in
04
pump.
(c) Why governing of turbine is required? Explain governing of Pelton
07
wheel with neat sketch.
OR
Q.5 (a) Describe working of hydraulic accumulator with neat sketch.
03
(b) Write short note on NPSH.
04
(c) Explain briefly different losses and efficiencies associated with
07
centrifugal pump.
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This post was last modified on 04 March 2021