B.TECH - Semester 4 fluid mechanics 2 Question Paper 2019 (jun)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Write short notes on (a) cavitation in turbines
- Write short notes on (b) multi-stage pumps
- 404 : FLUID MECHANICS - II (C) Time : 3 Hours Max. Marks : 100 PART - A Answer all questions. Each question carries 4 marks.
- (a) What do you mean by 'hydraulically best section'? State the conditions for maximum velocity and maximum discharge in circular section.
- (b) Explain gradually varied flow and the assumptions made.
- (c) What do you mean by separation of boundary layer? What is the effect of pressure gradient on boundary layer separation?
- (d) What are the different laws on which models are designed for dynamic similarity?
- (e) Write short notes on types of surge tanks. ( $5 \times 4=20$ Marks) P.T.O. Answer any one full question from each Module. Each full question carries 20 marks.
- (a) A 4 m diameter circular channel is laid at a bed slope of 1 in 800 . Find the depth, velocity and discharge for maximum velocity condition. Take $C=60.8$
- (b) What are the applications of specific energy in open channel flow?
- (c) Derive the Chezy's equation for an open channel flow. OR
- (a) A 8 m wide rectangular channel conveys 15 cumecs of water at a depth of 1.2 m Determine:
- (i) Specific energy of the flowing water, (ii) Critical depth, critical velocity and minimum specific energy, (iii) Froude number and state whether the flow is sub-critical or super critical.
- (b) Find the dimensions of an economical trapezoidal section of an open channel with side slope 2 H to 1 V , laid at a slope of 1 in 1600 to carry a discharge of $36 \mathrm{~m}^{3} / \mathrm{s}$. Take $\mathrm{C}=60$.
- (a) Find the slope of the free water surface in a rectangular channel of width 20 m , having depth of flow 5 m . The discharge through the channel is $50 \mathrm{~m}^{3} / \mathrm{s}$. The bed of the channel is having a slope of 1 in 4000 . Take $C=6...
- (b) Find the rate of change of depth of water in a rectangular channel of 10 m wide and 1.5 m deep, when the water is flowing with a velocity of $1 \mathrm{~m} / \mathrm{s}$. The flow of water through the channel of bed slope 1 in 4000 is regulated i...
- (a) A 3 m wide rectangular channel discharges $5.1 \mathrm{~m}^{3} / \mathrm{s}$, the depth of flow being 0.75 m . If due to a sudden release of flow, the upstream discharge rate is doubled, find the velocity of the consequent surge. Find also the ne...
- (b) A rectangular channel 2 m wide conveys water at a velocity of $2 \mathrm{~m} / \mathrm{s}$, the depth of flow being 1.25 m . The rate of flow at the downstream end is suddenly decreased such that the depth of flow is increased to 2 m . Find the a...
- (a) Define displacement thickness. Derive an expression for the displacement thickness.
- (b) A plate $450 \mathrm{~mm} \times 150 \mathrm{~mm}$ has been placed longitudinally in a stream of a crude oil of specific gravity 0.925 and kinematic viscosity of 0.9 stoke which flows with velocity of $6 \mathrm{~m} / \mathrm{s}$ calculate
- (i) The friction drag on the plate (ii) Thickness of the boundary layer at the trailing edge and (iii) Shear stress at the trailing edge.
- (a) Using Buckingham's $\pi$-theorem, show that the discharge $Q$ consumed by an oil ring is given by, $Q=N d^{3} \varphi\left[\mu / \rho N d^{2}, \sigma / \rho N^{2} d^{3}, w / \rho N^{2} d\right]$ Where d is the internal diameter of the ring, N is...
- (b) A spillway 7 m high and 150 m long discharge $2000 \mathrm{~m}^{3} / \mathrm{s}$ under a head of 4 m . If a $1: 16$ model of the spillway is to be constructed find the dimensions of the model and discharge in the model.
- (a) A pelton wheel is to be designed for the following specifications: shaft power $=11,772 \mathrm{~kW}$; Head $=380 \mathrm{~m}$; Speed $=750 \mathrm{rpm}$; Overall Efficiency $=86 \%$; Jet diameter is not to exceed one-sixth of the wheel diameter....
- (b) A turbine develops 9000 kW when running at 10 rpm . The head on the turbine is 30 m . If the head on the turbine is reduced to 18 m , determine the speed and power developed by the turbine.
- (a) Derive the expression for minimum starting speed of a centrifugal pump.
- (b) A Centrifugal pump while running at a net head of 1000 rpm discharges $80 \mathrm{~L} / \mathrm{sec}$ against a net head of 16 m . The manometric efficiency of the pump is 0.85 . If the vane angle at the outlet is $35^{\circ}$ and Velocity of flo...
- What are the different types of flow in open channels?
- With the help of sketches, explain velocity distribution in open channels.
- Explain specific energy curve with the help of sketches.
- Sketch and explain the possible gradually varied flow profiles in mild sloped channel.
- Explain Froude model law with some practical applications.
- Explain the applications of momentum equation.
- Explain the classification of turbines.
- What are air vessels? What are its functions? $$ (8 \times 5=40 \text { Marks }) $$ P.T.O. Answer any one full question from each module. Each full question carries 20 marks.
- (a) Derive Chezy's equation for uniform flow.
- (b) Determine the dimensions of the most economic section of a trapezoidal channel to carry a discharge of $15 \mathrm{~m}^{3} / \mathrm{s}$ at a slope of 1 in 4000 having side slopes 1 vertical to 2 horizontal. Assume Manning's $\mathrm{n}=0.015$.
- (a) Explain different types of jumps in a horizontal rectangular channel with neat sketches.
- (b) Calculate the critical depth and corresponding specific energy in a rectangular channel, 4 m wide carrying a discharge of $20 \mathrm{~m}^{3} / \mathrm{s}$. Assume Manning, $\mathrm{n}=0.014$ and bed slope 1 in 3000. Module - II
- (a) Derive dynamic equation for gradually varied flow mentioning the assumptions.
- (b) A 5 m wide rectangular channel carries a discharge of $15 \mathrm{~m}^{3} / \mathrm{s}$ of water. The bed slope of the channel is 1 in 200 and Manning's $n$ is 0.014 . Determine critical depth and normal depth. Also determine whether the channel ...
- (a) Explain Buckingham's $\Pi$ method of dimensional analysis.
- (b) Write short notes on
- (i) Distorted model (ii) Undistorted model (iii) Scale effect in models
- (a) Draw the velocity triangles of Pelton wheel bucket and obtain expressions for work done and efficiency.
- (b) A jet of water 40 mm in diameter having a velocity of $15 \mathrm{~m} / \mathrm{s}$ strikes normally a flat smooth plate. Determine the thrust and work done per second on the plate if the plate is moving at a velocity of $8 \mathrm{~m} / \mathrm{...
- Write short notes on (c) working of reciprocating pumps
- Write short notes on (d) indicator diagram.