An eddy current is a circular movement of fluid, such as air or water, that flows in a direction contrary to the main current. Eddy currents are common in rivers, oceans, and the atmosphere, and they play a significant role in the transport of sediments, nutrients, and pollutants. Understanding eddy currents is important in oceanography, atmospheric science, and sedimentology.
Reference: Mann, J., & Ott, S. (1994). “Horizontal Coherence of Eddies in the Surface Layer.” Boundary-Layer Meteorology, 70(1-2), 183-205.