Advection, in chemistry, mechanical and chemical engineering,'s a transport mechanism of a substance or a conserved property with a moving fluid. The fluid motion in advection's described mathematically as a vector field, and the material transported's typically described as a scalar concentration of substance, which's contained in the fluid. An example of advection's the transport of pollutants or silt in a river: the motion of the water carries these impurities downstream. Another commonly adv… (More on Advection)