Fluid Mechanics Questions and Answers

Fluid Mechanics Questions and Answers

1-An ideal flow is

(A) Viscous and compressible

(B) Inviscid and compressible

(C) Viscous and incompressible

(D) Inviscid and incompressible


2-Newton’s law of viscosity states that

(A) stress is proportional to strain

(B) stress is proportional to rate of strain

(C) stress is inversely proportional to strain

(D) stress is inversely proportional to rate of strain


3-Reynolds number is the ratio of

(A) Inertia force / Elastic force

(B) Inertia force / Viscous force

(C) Buoyancy force / Viscous force

(D) Buoyancy force / Inertia force


4-Moody diagram in fluid mechanics shows the relation between

(A) Friction factor and Reynolds number

(B) Heat transfer coefficient and Reynolds number

(C) Drag coefficient and Mach number

(D) Coefficient of discharge and Mach number


5-Boundary layer separation is caused by

(A) Reduction of pressure in the direction of flow

(B) Reduction of the boundary layer thickness

(C) Pressure of adverse pressure gradient

(D) Presence of favourable pressure gradient


6-For laminar flow through a pipe, the discharge varies

(A) As the square of diameter

(B) As the inverse of viscosity

(C) As the square of viscosity

(D) Inversely as the square of diameter


7-Velocity at a point in pipe flow may be measured by installing

(A) a wall tap

(B) a Venturimeter

(C) static pitot tube

(D) Rotameter


8-Inertia to gravity force ratio gives a non dimensional number called

(A) Reynolds number

(B) Froude number

(C) Cauchy number

(D) Mach number


9-The pipe carrying water from reservoir to the turbine house in a hydraulic power plant is called

(A) Supply pipe

(B) Inlet pipe

(C) Pen stock

(D) Draft tube


10-Kinematic viscosity is defined as equal to

(A) Dynamic viscosity x Density

(B) Dynamic viscosity / Density

(C) Dynamic viscosity x Pressure

(D) Pressure x Density


11-Surface tension has unit of

(A) Force per unit area

(B) Force per unit length

(C) Force per unit volume

(D) None of the above


12-Pascal’s law states that pressure at a point is equal in all directions

(A) In a liquid at rest

(B) In a fluid at rest

(C) In a laminar flow

(D) In a turbulent flow


13-Atmospheric pressure held in terms of water column is

(A) 2.8 meters

(B) 8.3 meters

(C) 9.8 meters

(D) 10.3 meters


14-Mach number is defined as the ratio of

(A) Inertia force to viscous force

(B) Viscous force to surface tension force

(C) Viscous force to elastic force

(D) Inertia force to elastic force


15-Total drag on a body is the sum of

(A) Pressure drag and velocity drag

(B) Pressure drag and friction drag

(C) Friction drag and velocity drag

(D) None of the above



1-(D), 2-(B), 3-(B), 4-(A), 5-(C), 6-(B), 7-(C), 8-(B), 9-(C), 10-(B), 11-(A), 12-(B), 13-(D), 14-(D), 15-(B)