Test: Kinetic Energy Correction Factor - Civil Engineering (CE) MCQ

Kinetic energy correction factor(α): 

• It is defined as the ratio of kinetic energy/second based on actual velocity to the kinetic energy/second based on average velocity.
• 
• where A = area, V= average velocity, u= local velocity at distance r.
• In circular pipe laminar flow α = 2

It is assumed in the derivation of Bernoulli equation that the velocity at the both end sections is uniform. But in a practical situation this may not be the case and the velocity can very across the cross section. A remedy is to use a correction factor for the kinetic energy term in the equation. Its value for a fully developed laminar pipe flow is around 2, whereas for a turbulent pipe flow it is between 1.04 to 1.11. It is usual to take it is 1 for a turbulent flow. It should not be neglected for a laminar flow.  

Kinetic energy correction factor(α): 

• It is defined as the ratio of kinetic energy/second based on actual velocity to the kinetic energy/second based on average velocity.
• 
• where A = area, V= average velocity, u= local velocity at distance r.
• For laminar flow in a circular pipe α = 2  

Kinetic energy factor for a fully developed laminar flow is around 2. Laminar flow occurs when a fluid flows in parallel layers. The flow must not have any sort of disruption between the layers of fluid. The fluid flows without a lateral mixing which makes it slide past one another.

Kinetic energy depends upon velocity and mass. The relation between K.E with mass and velocity is K.E = 0.5mv². If we double the kinetic energy, the velocity has to be increased by a factor equal to the square root of two.

When the bullet is released from the gun, it moves through the individual air molecules. These molecules tend to vibrate which cannot be seen though our naked eye. The solid block acts as a “momentum sink”. It’s so big when compared to a tiny bullet that it can absorb all the momentum without visibly moving.

The kinetic energy remains a constant as the magnetic field always exerts a force perpendicular to the particle’s velocity. So, there is no change in the velocity of the fluid. Therefore, kinetic energy remains the same.

Since the collision is elastic, the cricket ball having a higher mass than that of the tiny table tennis ball will hit and generate a higher velocity. After immediate impact, the table tennis ball will move exactly with twice the velocity of the cricket ball.

This is mainly because, Bernoulli’s equation is applied only when the fluid is irrotational. It means that the stream lines are not supposed to intersect each other. Also, the equation does not take viscosity into account. Thus, the flow rate decreases when you close the valve.

Reynolds number is a dimensionless quantity. It is used to predict flow patterns in different types of fluid flow. At lower Reynold’s number, the flow is laminar. At higher Reynolds number, the flow is turbulent.