Physics

Fluid Mechanics and Hydraulics

361 Questions

Fluid mechanics and hydraulics questions address the principles of fluid flow, pipe resistance, and open channel dynamics. The topics include Bernoulli equation, Navier-Stokes equation, and hydrograph calculations. These concepts are crucial for civil and mechanical engineering competitive examinations.

Fluid flow equationsOpen channel flowPipe frictionHydraulic jumpHydrograph analysis

Fluid Mechanics and Hydraulics Questions

Multiple choice

What is the relationship between lift force and angle of attack in a fluid?

  1. Linear

  2. Exponential

  3. Quadratic

  4. Inversely proportional
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lift force is proportional to the angle of attack of the object in a fluid.

Multiple choice

What is the NPSH (Net Positive Suction Head) of a pump?

  1. The difference between the atmospheric pressure and the pressure at the pump inlet

  2. The difference between the pressure at the pump inlet and the vapor pressure of the liquid

  3. The difference between the pressure at the pump outlet and the atmospheric pressure

  4. The difference between the pressure at the pump outlet and the vapor pressure of the liquid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

NPSH (Net Positive Suction Head) is the difference between the pressure at the pump inlet and the vapor pressure of the liquid. A higher NPSH value indicates that the pump is less likely to experience cavitation.

Multiple choice

What is the term used to describe the pressure exerted by a fluid in a reservoir?

  1. Reservoir pressure

  2. Pore pressure

  3. Bottomhole pressure

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Reservoir pressure, pore pressure, and bottomhole pressure are all terms used to describe the pressure exerted by a fluid in a reservoir.

Multiple choice

Darcy's Law states that the discharge velocity (v) through a soil is:

  1. $v = ki$
  2. $v = k/i$
  3. $v = i/k$
  4. $v = k^2i$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Darcy's Law states that the discharge velocity (v) through a soil is directly proportional to the hydraulic gradient (i) and the coefficient of permeability (k).

Multiple choice

A soil has a hydraulic conductivity of 2.5 x 10^-4 m/s. Calculate the discharge velocity through the soil if the hydraulic gradient is 0.2.

  1. 5.0 x 10^-5 m/s

  2. 5.0 x 10^-4 m/s

  3. 2.0 x 10^-5 m/s

  4. 2.0 x 10^-4 m/s
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using Darcy's Law, v = ki, the discharge velocity (v) can be calculated as 2.5 x 10^-4 m/s * 0.2 = 5.0 x 10^-5 m/s.

Multiple choice

How is the thickness of a penstock determined?

  1. Based on the water flow rate

  2. Based on the height of the reservoir

  3. Based on the length of the penstock

  4. Based on the pressure exerted by the water
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The thickness of a penstock is primarily determined by the pressure exerted by the water flowing through it. Higher pressure requires thicker penstocks to ensure structural integrity.

Multiple choice

In an open channel, the velocity distribution is typically:

  1. Uniform

  2. Parabolic

  3. Triangular

  4. Rectangular
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The velocity distribution in an open channel is typically parabolic, with the highest velocity occurring at the surface and decreasing towards the bottom.

Multiple choice

The specific energy of a flow in an open channel is defined as:

  1. Total energy per unit weight

  2. Potential energy per unit weight

  3. Kinetic energy per unit weight

  4. Internal energy per unit weight
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Specific energy is the total energy per unit weight of the fluid and is a constant along a streamline.

Multiple choice

The critical depth in an open channel is the depth at which:

  1. Flow is most efficient

  2. Specific energy is minimum

  3. Froude number is unity

  4. Velocity is maximum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Critical depth is the depth at which the Froude number is unity, indicating the transition between subcritical and supercritical flow.

Multiple choice

The Manning equation is commonly used to calculate:

  1. Velocity in an open channel

  2. Discharge in an open channel

  3. Depth of flow in an open channel

  4. Slope of an open channel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Manning equation is an empirical equation used to calculate the velocity of flow in an open channel.

Multiple choice

The Chezy equation is an alternative formula for calculating:

  1. Velocity in an open channel

  2. Discharge in an open channel

  3. Depth of flow in an open channel

  4. Slope of an open channel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Chezy equation is an alternative formula to the Manning equation for calculating the velocity of flow in an open channel.

Multiple choice

The gradually varied flow (GVF) analysis is used to study:

  1. Flow in a channel with constant slope and cross-section

  2. Flow in a channel with varying slope and cross-section

  3. Flow in a channel with a sudden change in slope or cross-section

  4. Flow in a channel with a hydraulic jump
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

GVF analysis is used to study the flow in a channel with varying slope and cross-section, where the flow properties change gradually along the channel.

Multiple choice

The concept of normal depth is associated with:

  1. Uniform flow in an open channel

  2. Critical flow in an open channel

  3. Supercritical flow in an open channel

  4. Subcritical flow in an open channel
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Normal depth is the depth of flow in an open channel at which uniform flow conditions exist.

Multiple choice

The energy equation for open channel flow is derived from:

  1. Conservation of mass

  2. Conservation of energy

  3. Conservation of momentum

  4. Conservation of angular momentum
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The energy equation for open channel flow is derived from the principle of conservation of energy.

Multiple choice

The momentum equation for open channel flow is derived from:

  1. Conservation of mass

  2. Conservation of energy

  3. Conservation of momentum

  4. Conservation of angular momentum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The momentum equation for open channel flow is derived from the principle of conservation of momentum.