What does the term "entrain" refer to in the context of water?

The term "entrain" in the context of water generally refers to the process of mixing or involving a solid or particle within a fluid, often leading to the trapping of those solids in the flow. When solid materials or bubbles are "entrained" in a liquid medium, they are carried along with the fluid, effectively becoming a part of that fluid flow. This is a vital concept in various fields, including environmental engineering and fluid dynamics, as it influences the behavior of sediments in rivers, the distribution of pollutants, and the design of infrastructure like pipelines and treatment plants.

The idea of entraining bubbles specifically highlights how air or gas can be included within the water, impacting flow characteristics and potentially influencing processes such as aeration in water treatment or creating certain water features. This understanding is essential for recognizing how different actions, such as agitation or movement, can affect the composition and behavior of water mixtures in practical applications.