What is the term for the technique of introducing air into the water flow to reduce the actual flow while maintaining high-volume perception in faucets and shower-heads?

The technique referred to in the question is known as aeration. This process involves introducing air into the water stream, which can effectively reduce the water flow rate while still allowing for a high perceived volume at the faucet or showerhead. By mixing air with the water, aerators create a foamy or bubbly mixture. This not only enhances the water's flow characteristics but also improves the user experience, making it feel like a stronger flow without the actual volume being as high.

Aeration is widely used in plumbing fixtures to conserve water, making it an essential technique in modern plumbing design focused on sustainability. It helps in achieving compliance with regulations aimed at reducing water consumption, thereby contributing to environmental conservation efforts.

Other terms listed, such as filtration, compression, and centrifugation, refer to different processes unrelated to the concept of modifying water flow through the addition of air. Filtration involves removing impurities from water; compression relates to reducing the volume of gases or liquids; and centrifugation is a technique used to separate substances based on density. These processes do not align with the concept of enhancing perceived water flow through air introduction.