GERTC HPGE Terms: Fluid Mechanics

cannot remain at rest under action of any shear force

Fluid is a substance that

4°C

Density of water is maximum at

cohesion

Property of a fluid by which its own molecules are attracted is called

adhesion

Property of a fluid by which molecules of different kinds of fluids are attracted to each other is called

it is at rest

The normal stress in a fluid will be constant in all directions at a point only if

dissolved air, dissolved, salt, and suspended matter

Specific weight of sea water is more that of pure water because it contains

surface tension

Free surface of a liquid tends to contract to the smallest possible area due to force of

greater

A liquid would wet the solid, if adhesion forces as compared to cohesion forces is

atmospheric pressure

Barometer is used to measure

pressure in pipes, channels etc.

Manometer is used to measure

lower than the surface of liquid

If cohesion between molecules of a fluid is greater than adhesion between fluid and glass, then the free level of fluid in a dipped glass tube will be

compressibility

When a fluid is subjected to resistance, it undergoes a volumetric change due to

Pascal's law

Liquids transmit pressure equally in all the directions. This is according to

decrease

The rise or depression of liquid in a tube due to surface tension with an increase in size of tube will

the height of barometer will be less and its vapor pressure is so low that it may be neglected

Mercury is often used in barometer because

center of pressure

The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as

cp is either at cg or below it

Which of the following is the correct relation between centroid (cg) and the center of pressure (cp) of a plane submerged in a liquid?

the area is horizontal, vertical, or inclined

The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at the centroid, if

D. The vertical component passes through the center of pressure of the volume

Choose the wrong statement:

A. The horizontal component of the hydro-static force on any surface is equal to the normal force on the vertical projection of the surface

B. The horizontal component acts through the

center of pressure for the vertical projection

C. The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area

D. The vertical component passes through the

center of pressure of the volume

below the centroid

Center of pressure on an inclined plane

is

No

Can center of pressure for a vertical plane submerged surface be ever be above center of gravity?

False

In a vertically submerged plane surface, pressure at every point remains same. True or False?

True

For an inclined plate the pressure intensity at every point differs. True or False?

False

The magnitude of total pressure and center of pressure is independent on the shape of the submerged plane surface. True or False?

Linear

What is the variation of total pressure with depth for any submerged surface if we neglect variation in the density?

Archimedes' principle

The resultant upward pressure of a fluid on a floating body is equal to the weight of the fluid displaced by the body. This definition is according to

buoyant force

The resultant upward pressure of the fluid on an immersed body is called

Displacement of fluid due to

submerged body

What is the principal cause of action of buoyant force on a body submerged partially or fully in fluid?

center of buoyancy

The center of gravity of the volume of the liquid displaced by an immersed body is called

zero

The horizontal component of buoyant force is

centroid of the displaced volume of fluid

The line of action of the buoyant force acts through the

D. Center of buoyancy is located above the center of gravity of the displaced liquid

Choose the wrong statement

A. Any weight, floating or immersed in a liquid, is acted upon by a buoyant force B. Buoyant force is equal to the weight of the liquid displaced

C. The point through which buoyant force acts, is called the center of buoyancy

D. Center of buoyancy is located above the

center of gravity of the displaced liquid

weight of the fluid displaced by the body

According to the principle of buoyancy a

body totally or partially immersed in a

fluid will be lifted up by a force equal to

By altering the shape

How can relatively denser object be made to float on the less dense fluid?

A. the metacenter should lie above the center of gravity

B. the center of buoyancy and the center of gravity must lie on the same vertical line

C. a righting couple should be formed

The conditions for the stable equilibrium of a floating body are

the center of gravity of the body and the meta center

Metacentric height is given as the distance between

buoyant force and the center line of body

Metacenter is the point of intersection of

metacenter

When a body floating in a liquid, is displaced slightly, it oscillates about

neutral equilibrium

When the ship's metacenter and center of gravity coincide at same point then the vessel is said to be in

potential, kinetic and pressure

heads

Energy gradient line takes into consideration

potential and pressure heads only

Hydraulic gradient line takes into consideration

A. EGL always drops in the direction of flow

Which of the following is true?

A. EGL always drops in the direction of flow

B. EGL always rises in the direction of flow

C. EGL always remains constant in the direction of flow

D. EGL may or may not change in the direction of flow

A. HGL will never be above EGL

Which of the following is true?

A. HGL will never be above EGL

B. HGL will never be under EGL

C. HGL will never coincide with EGL

D. HGL will may or may not be above EGL

kinetic head

The vertical intercept between EGL and HGL is equal to

equal than that of EGL for a pipe of uniform cross-section

The slope of HGL will be

mass

Equation of continuity is based on the principle of conservation of

energy

Bernoulli's equation deals with the law of conservation of

length

All the terms of energy in Bernoulli's equation have dimension of

A. Friction of surface

B. Sudden enlargement or contraction

of area

C. Any obstruction in the path of flow

The losses of energy in pipes due to

friction

The major loss of energy in long pipes is due to

frictional loss

Which one of the following is a major loss?

A. sudden enlargement in the pipe

B. sudden contraction in the pipe

C. bends in pipe

Minor losses occur due to

long pipes

Minor losses do not make any serious effect in

the discharge is same through each pipe

In series - pipe problems

The rate of discharge in the main line is equal to the sum of discharges in each of the parallel pipes

Which of the following conditions is valid in the case of flow through parallel pipes?

head loss and discharge are same in two systems

Two pipe systems are said to be equivalent when

kinematic viscosity

The ratio of absolute viscosity to mass density is known as

A. speed at which the valve is closed

B. length of the pipe

C. elastic properties of the pipe material

The magnitude of water hammer effect in a pipe depends on

when fluid is suddenly brought to rest by closing the valve

The phenomenon of water hammer takes place in pipes

slow closing valves

Water hammer pressure can be considerably reduced using

Froude's number

The ratio of inertia force and gravitational force is called as

Hydraulic radius

Which geometric parameter determines the efficiency of the channel?

Wetted perimeter

For a channel to be economic which of the following parameters should be minimum?

0.81D

What is the depth of flow in case most economical circular section considering maximum velocity?

Difference of pressure between two points

Differential manometer is used to measure

Velocity, depth, pressure, etc. change from point to point in the fluid flow

Non uniform flow occurs when

Concave

When a tube of smaller diameter is dipped in water, the water rises in the tube with an upward __________ surface.

Surface tension

The tendency of a liquid surface to contract is due to the following property

Gauge pressure

The pressure measured with the help of a pressure gauge is called

A. Surface tension

B. Cohesion of the liquid

C. Adhesion of the liquid molecules and the molecules on the surface of a solid

Capillary action is due to the

Increases

The intensity of pressure on an immersed surface __________ with the increase in depth.

Force of cohesion

Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the

Pressure head

The hydraulic gradient line lies over the centre line of the pipe by an amount equal to the