Fluid Mechanics_AJ_Professional_Services

Water flows through a sharp-edged orifice 2 cm in diameter in a partition wall that maintains constant water levels on the two sides as shown by the figure below. The flow rate (m^3/day) is most nearly:

• 50

• 52

• 60

• 73

A pitot tube is used to measure the velocity of air. It shows a pressure of 0.53 m of Mercury (Hg). Assume that the air has a static pressure of 70 kPa and density of 1.2 kg/m^3. The specific gravity of Mercury (Hg) is 13.6. The velocity (m/sec) of the flow is most nearly:

• 24

• 29

• 34

• 38

A piezometer and a pitot tube are tapped into a horizontal pipe as shown in the figure to measure static and stagnation pressures. Th fluid in the tube has a specific gravity of 1.5 and the upper portion of the manometer contains air. For the indicated water column heights, the velocity (m/sec) of the fluid at the center of the pipe is most nearly:

• 1.17

• 1.53

• 2.08

• 2.24

A pitot tube is used to measure the air flow rate of a pipe as shown in the figure below. The specific gravity of the manometer liquid is 0.85 and the density of air is 1.2 kg/m^3. Assume the unit weight of the water is 9810 N/m^3. The velocity of air (m/sec) in the tube is most nearly:

• 0.82

• 1.8

• 23.6

• 25.6

Which of the following statements are true regarding viscosity? Select all that apply:

• Viscosity is liquid's resistance to flow.

• Viscosity decreases with a decrease in temperature.

• Viscosity is not related to the forces between molecules in a liquid.

• Viscosity increases as molecular weight and intermolecular forces increase.

• Viscosity is due to the internal frictional force that develops between different layers of liquid as they are forced to move relative to each other.

Newton's law of viscosity depends upon the:

• Stress and strain in a fluid

• Shear stress, pressure, and velocity

• Shear stress and rate of strain

• Viscosity and shear stress

Decrease in temperature, in general, results in:

• An increase in viscosities of both gases and liquids

• A decrease in the viscosities of both liquids and gases

• An increase in the viscosity of liquids and a decrease in that of gases

• A decrease in the viscosity of liquids and an increase in that of gases

Kinematic viscosity:

• is the proportionality constant relating shearing stress to the rate of angular deformation

• is expressed in units of shear stress times the time interval

• is found by dividing the absolute viscosity by the mass density at the same temperature

• is not related to the density of a fluid

Water at temperature of 10 deg C flows through a 150-mm diameter galvanized iron pipe. The average flow velocity is 4 m/sec. What is the pressure loss due to friction across a 100 m length of this pipe:

• 3 m

• 9 m

• 11 m

• 16 m

The level in a retention basin is normally controlled with an outlet pipe as shown in the figure below. The pipe has a diameter of 1.78 cm. The equivalent length of the pipe (including the elbows, entrance effect, and discharge) is 10.0 m. The fluid properties are provided in the figure. Assuming a Reynolds number of 80,000 and a friction factor of 0.033, the head loss due to flow is most nearly:

• 7.35

• 19.1

• 4.25

• 20.5