Venturi effect
Figure 1. A diagram demonstrating the Venturi effect. The fluid flows faster in at point 2 than at point 1 due to the decrease in cross-sectional area. The pressure at point 1 is higher however, due to the conservation of energy.[1]
The Venturi effect describes how the velocity of the fluid increases (thus increasing the kinetic energy of the water) as the cross section of the container decreases, like in a funnel. In the case of tidal stream generators a duct or shroud (otherwise known as a diffuser) can be used to increase the amount of power available. A funnel shape is built around or near the turbine that causes the flow rate of the water to accelerate - sometimes dramatically. These can cause up to 4 or 5 times higher power output than a similar sized turbine without a shroud because it's harnessing the energy from a greater amount of water.[2]
Many different styles of tidal stream generators can harness the Venturi effect.
References
- ↑ Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/5/54/Venturifixed2.PNG
- ↑ Wise Geek. (August 7, 2015). What is a Venturi tube? [Online], Available: http://www.wisegeek.com/what-is-a-venturi-tube.htm
