Eddy (fluid dynamics)

An eddy in fluid dynamics is a circular or spiral current of fluid that forms when the main flow of a liquid or gas becomes disrupted, creating a whirling motion like a tiny whirlpool. These eddies occur naturally in many places you might observe, such as the swirling water behind a boat, the spiraling air above a hot surface, or even the turbulent clouds in a storm. Understanding eddies helps scientists and engineers predict how fluids behave and can improve everything from airplane design to weather forecasting.