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.