71. The energy equation, E + P/ρ + V²/2g +gZ (E = internal energy/mass), is applicable to
Perfect gases only
Isothermal flow of gases
Adiabatic unsteady flow of gases
All of the above
✅ The correct answer is option D.
Fluid Mechanics MCQs
72. Boundary layer separation is characterised by one of the conditions given below, where ‘Re’ is the Reynolds number for the flow. Select the appropriate conditions.
Re << 1, accelerating flow
Re >> 1, accelerating flow
Re << 1, decelerating flow
Re >>1, decelerating flow
✅ The correct answer is option D.
73. The ratio of pressure forces to inertial forces is called the __________ number.
Froude
Euler
Reynold
Mach
✅ The correct answer is option B.
74. For laminar flow of Newtonion fluid in a circular pipe, the velocity distribution is a function of the distance ‘d’ measured from the centre line of the pipe, and it follows a __________ relationship.
Logarithmic
Parabolic
Hyperbolic
Linear
✅ The correct answer is option B.
75. A fluid element has a velocity V = -y² . xi + 2yx² . j. The motion at (x, y) = (l/√2, 1) is
Rotational and incompressible
Rotational and compressible
Irrotational and compressible
Irrotational and incompressible
✅ The correct answer is option B.
76. Which law/principle of solid mechanics is similar/equivalent to Newton’s law of viscosity in fluid mechanics?
Archimedes principle
Newton
Hooke
Newton
✅ The correct answer is option C.
77. For laminar flow through a closed conduit
Vmax = 2Vav
Vmax = Vav
Vmax = 1.5Vav
Vmax = 0.5Vav
✅ The correct answer is option A.
78. Mach number is important in a fluid flow problem, when the inertia and __________ forces predominate.
Elastic
Viscous
Gravity
None of these
✅ The correct answer is option A.
79. A piezometer opening measures the __________ fluid pressure.
Static
Undisturbed
Total
Dynamic
✅ The correct answer is option B.
80. The discharge through a semi-circular weir varies as (where, H = Head of liquid.)
H
H2
H3/2
H1/2
✅ The correct answer is option B.