Fluid Mechanics

Power required in high Reynolds number mixing is proportional to the fifth power of the impeller diameter:

Doubling the impeller diameter results in a -fold increase in power requirement.

The bulk modulus ( ) is calculated using:

Substituting and , we find:

The flow type is determined using the Reynolds number formula:

Given and kinematic viscosity the calculated Reynolds number is below 2000, indicating laminar flow.

Head loss in flow measuring devices increases in the following order:

1. Flow nozzle: Causes the least head loss due to its streamlined design.
2. Venturimeter: Has slightly higher head loss than a flow nozzle but remains efficient.
3. Orifice meter: Causes the highest head loss due to abrupt changes in flow direction and a larger pressure drop.

The given problem involves the calculation of the length of the weir using the formula for discharge over a rectangular weir:

where is the discharge, is the length of the weir, is the head, and is the coefficient of discharge. Substituting the values , , and (assumed standard value), the calculated length of the weir comes out to be approximately .

Step 1: Understanding Hydraulic Transmission Liquids.
Hydraulic transmission systems require liquids with specific properties, such as being incompressible and providing lubrication. The most commonly used liquid for this purpose is oil.

Step 2: Analysis of options.
- (A) oil: Oil is the most commonly used fluid in hydraulic systems.
- (B) water: Water is used in some systems but is less common due to its lower lubricating properties.
- (C) steam: Steam is not used in hydraulic systems due to its compressibility.
- (D) any volatile liquid: Volatile liquids are generally not suitable because they may evaporate or cause instability in hydraulic systems.

Step 3: Conclusion.
The correct answer is (A) oil, as it is the most commonly used liquid in hydraulic transmission.