Fluid dynamics is "the branch of engineering that's concerned with the movement of liquids and gases," according to the American Heritage Dictionary. Fluid dynamics is one of two branches of hydraulics , which is that the study of fluids and therefore the way forces affect them. (The other branch is fluid statics, which deals with fluids at rest.)
Scientists across several fields study fluid dynamics. Fluid dynamics provides methods for studying the evolution of stars, ocean currents, weather patterns, tectonics and even blood circulation. Some important technological applications of fluid dynamics include rocket engines, wind turbines, oil pipelines and air conditioning systems.
The movement of liquids and gases is typically mentioned as "flow," a thought that describes how fluids behave and therefore the way they interact with their surrounding environment — as an example , water moving through a channel or pipe, or over a surface. Flow are often either steady or unsteady