1.

Segment V5.1: Sink Overflow
(Related to Textbook Section 5.1 - Conservation of Mass - The Continuity Equation)

For incompressible flow, the volume flowrate into a control volume equals the volume flowrate out of it.

The overflow drain holes in a sink must be large enough to accommodate the flowrate from the faucet if the drain hole at the bottom of the sink is closed. Since the elevation head for the flow through the overflow drain is not large, the velocity there is relatively small. Thus, the area of the overflow drain holes must be larger than the faucet outlet area.

2.

Segment V5.2: Shop Vac Filter
(Related to Textbook Section 5.1 - Conservation of Mass - The Continuity Equation)

For incompressible flow through a device, the volume flowrate (flow area times the average normal velocity) is constant.

The air velocity at the inlet nozzle of a shop vac is quite large (about 100 ft/s) and the flow area is relatively small (about 1.5 square in.). Within the vacuum cleaner the air passes through a large-area, folded paper filter (about 1500 square in.) with a small average velocity (about 0.1 ft/s). The filter provides a large particle collection surface with a small velocity and pressure drop across it.

3.

Segment V5.3: Smokestack Plume Momentum
(Related to Textbook Section 5.2.2 - Application of the Linear Momentum Equation)

A change in the momentum of a fluid (such as a change in speed or direction of flow) requires a non-zero resultant force.

The exhaust gas flowing within a smokestack has vertical momentum only. As the fluid leaves the stack it interacts with the horizontal wind. This interaction produces a non-zero force on the exhaust gas and causes it to develop a horizontal motion. In addition, the vertical momentum is lost to the surrounding air and the exhaust gas eventually flows along with the wind.

4.

Segment V5.4: Force Due to a Water Jet
(Related to Textbook Section 5.2.2 - Application of the Linear Momentum Equation)

A jet of fluid deflected by an object puts a force on the object. This force is the result of the change of momentum of the fluid and can happen even though the speed (magnitude of velocity) remains constant.

If a jet of water has sufficient momentum, it can tip over the block that deflects it. The same thing can happen when a garden hose is used to fill a sprinkling can. Similarly, a jet of water against the blades of a Pelton wheel turbine causes the turbine wheel to rotate.

5.

Segment V5.5: Rotating Lawn Sprinkler
(Related to Textbook Section 5.2.4 - Application of the Moment-of-Momentum Equation)

The net rate of flow of moment-ofmomentum through a control surface equals the net torque acting on the contents of the control volume.

Water enters the rotating arm of a lawn sprinkler along the axis of rotation with no angular momentum about the axis. Thus, with negligible frictional torque on the rotating arm, the absolute velocity of the water exiting at the end of the arm must be in the radial direction (i.e., with zero angular momentum also). Since the sprinkler arms are angled "backwards", the arms must therefore rotate so that the circumferential velocity of the exit nozzle (radius times angular velocity) equals the oppositely directed circumferential water velocity.

6.

Segment V5.6: Impulse-Type Lawn Sprinkler
(Related to Textbook Section 5.2.4 - Application of the Moment-of-Momentum Equation)

The operation of an impulse-type lawn sprinkler is based on the linear momentum and angular momentum of water jets and oscillating solid components.

A set of linkages, switched by stops on the sprinkler base, controls the flow of the water jet. For one setting of the linkages, the periodic off-set of the jet causes the sprinkler head to slowly rotate. For the other setting, the angular impulse of the oscillating arm against the sprinkler head causes it to rotate in the opposite direction. A careful inspection of the actual device is needed to obtain a complete understanding of how it works.

7.

Segment V5.7: Energy Transfer
(Related to Textbook Section 5.3.2 - Application of the Energy Equation)

Various types of energy occur in flowing fluids.

Work must be done on the device shown to turn it over because the system gains potential energy as the heavy (dark) liquid is raised above the light (clear) liquid. This potential energy is converted into kinetic energy which is either dissipated due to friction as the fluid flows down the ramp or is converted into power by the turbine and then dissipated by friction. The fluid finally becomes stationary again. The initial work done in turning it over eventually results in a very slight increase in the system temperature.

8.

Segment V5.8: Water Plant Aerator
(Related to Textbook Section 5.3.3 - Comparison of the Energy Equation with the Bernoulli Equation)

The energy equation is often written in terms of energy per unit weight (head) and relates the velocity, elevation, pressure, and pump heads to the head loss.

A water aerator at a water treatment plant is governed by energy concepts. The pump driving the flow adds a head (pump head) to raise the water to the top of the aerator (elevation head). Too much pump head would either produce too big a flowrate or force the water up too high. Most of the head added by the pump is lost (head loss) as the water tumbles down the column, mixing with the air.