GATE 2015 FLUID MECHANICS - XE-B
B : FLUID MECHANICS
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Q. 1 – Q. 9 carry one mark each.
Q.1 The gap d between two concentric cylinders, each of height h, is filled with an oil. The torque required to rotate the inner cylinder at an angular velocity of ? against the fixed outer cylinder is T. The diameter of the inner cylinder is d and d << d. The dynamic viscosity of the oil is given by
(A) 4pdt / d3?h (B) 48T / pd3?h (C) 4pdt / d2?h2 (D) 48T / pa?h3
Q.2 Water is retained against a sluice gate in the form of a circular segment as shown in the figure. If ? and g are the density of water and gravitational acceleration respectively, the upward force exerted by the gate on the water per unit depth perpendicular to the plane of the figure is
(A) ?R2 (? – 1/2 sin 2?) g (B) ?R2 (cos2 ? – 1/2 sin ?) g(C) ?R2 (cos ? – 1/2 sin ?) g (D) ?R2 (cos2 ? – 1/2 sin2 ?) g
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Q.3 A two-dimensional velocity field is given by V = 10(y3 – x2y)î + 2Cxy2j, where î and j are the unit vectors in the directions of the rectangular Cartesian coordinates x and y, respectively. If the flow is incompressible, the constant C should be
(A) -10 (B) 0 (C) 5 (D) 10
Q.4 Let V and T denote the velocity vector and temperature in a flow field. The rate of change of temperature experienced by a fluid particle as it is passes through the point (x1, y1, z1) at a time t1 is 2.5 °C/s. The rate of change of temperature at a time t1 at the point (x1, y1, z1) is 4.8 °C/s. The quantity V.?T at (x1, y1, z1) and t1 in °C/s is
XE-B 1/6
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GATE 2015 FLUID MECHANICS – XE-B
Q.5 In a simple Couette flow apparatus, the gap h between the parallel plates is filled with a liquid of density ? and dynamic viscosity µ, and one plate is dragged at a velocity of U parallel to itself, while the other plate is fixed. The magnitude of vorticity at any point in the flow is
(A) µ / ?h2 (B) 0 (C) 1/2 µU / h2 (D) U / h
Q.6 An open glass capillary tube of 2 mm bore is lowered into a cistern containing mercury (density = 13600 kg/m3 ) as shown in the figure. Given that the contact angle between mercury and glass = 140°, surface tension coefficient = 0.484 N/m and gravitational acceleration = 9.81 m/s2, the depression of mercury in the capillary tube below the free surface in the cistern, in mm, is .
(A) po – 1/2 ?2 R2 (B) po – ?2 R2 (C) po + ?2 R2 (D) po + ?2 R2
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Q.8 The following is true at the point of separation of a boundary layer:
(A) Transition occurs from laminar to turbulent flow
(B) The flow relaminarizes from turbulent regime
(C) The shear stress vanishes
(D) The relation between stress and rate of strain ceases to be linear
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Q.9 A certain fluid flow phenomenon is described by Reynolds, Weber and Ohnesorge numbers. The Weber and Ohnesorge numbers are defined as We = ?U2L / s and Oh = µ / v?sL' respectively, where s is the surface tension, ? is the density, µ is the dynamic viscosity, U is the velocity and L is the characteristic dimension. If Re denotes the Reynolds number, which of the following relations is true?
XE-B (A) We=Oh Re2 (B) We= Oh2 Re2 (C) We=Oh2 Re (D) We=Oh Re
2/6
GATE 2015 FLUID MECHANICS - XE-B
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Q. 10 – Q. 22 carry two marks each.
Q.10 A rectangular boat 6 m wide and 15 m long (dimension perpendicular to the plane of the figure) has a draught of 2 m. The side view of the boat is as shown in the figure. The centre of gravity G of the boat is at the free surface level. The metacentric height of the boat in m is
(A) -1.0 (B) 0.5 (C) 1.5 (D) 2.0
This download link is referred from the post: RGUHS M.Pharm Last 10 Years 2011-2021 Previous Question Papers || Rajiv Gandhi University of Health Sciences
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