Fluid Mechanics

281.In case of Couette flow, the fluid flow is between two large flat parallel plates with

1. Top plate moving and the bottom plate fixed
2. Bottom plate moving and the top plate fixed
3. Both the plates fixed
4. Both the plates moving

282.In case of end to end connection of two or more pipes in series, the _________ each pipe.

1. Same rate of flow passes through
2. Head loss is same through
3. Rate of flow in each pipe is proportional to the length of
4. Total flow rate is the sum of flow rate in

283.In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of

1. Relative roughness
2. Absolute roughness
3. Friction co-efficient for flows at equal Reynold number
4. All (A), (B) & (C)

284.In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas).

1. 1/√M
2. √M
3. 1/M
4. M

285.In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where, T = absolute temperature).

1. 1/√T
2. 1/T
3. √T
4. T

286.In case of laminar flow of fluid through a circular pipe, the

1. Shear stress over the cross-section is proportional to the distance from the surface of the pipe
2. Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder
3. Velocity profile varies hyperbolically and the shear stress remains constant over the crosssection
4. Average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)

287.In case of supersonic flow of a fluid through pipeline, the 'Mach number' is

1. 0
2. 1
3. < 1
4. > 1

288.In case of turbulent flow of a Newtonian fluid in a straight pipe, the maximum velocity is equal to (where, V_avg = average fluid velocity)

1. V_avg
2. 1.2 V_avg
3. 1.5 V_avg
4. 1.8 V_avg

289.In case of turbulent flow of fluid through a circular pipe, the

1. Mean flow velocity is about 0.5 times the maximum velocity
2. Velocity profile becomes flatter and flatter with increasing Reynolds number
3. Point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius)
4. Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more

290.In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow?

1. Discharge of water by a centrifugal pump being run at a constant rpm
2. Water flow in the suction and discharge pipe of a reciprocating pump
3. Water discharge from a vertical vessel in which constant level is maintained
4. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe