In the chemical and other processing industries, many operations are dependent to a great extent on effective agitation and mixing of fluids. Generally, agitation refers to forcing a fluid by mechanical means to flow in a circulatory or other pattern inside a vessel. Mixing usually implies the taking of two or more separate phases, such as a fluid and a powdered solid or two fluids, and causing them to be randomly distributed through one another.
There are a number of purposes for agitating fluids, some of which are briefly summarized:
Blending of two miscible liquids, such as ethyl alcohol and water.
Dissolving solids in liquids, such as salt in water.