The process of manufacturing things out of melted metal obviously involves the study of how liquid metals flow. Melted glasses and plastics are also examples of fluids whose flow often needs to be understood in order to design manufacturing processes. Power generation almost always involves fluid flow. Many natural and biological systems involve interesting fluid flow problems. Plankton, nutrients and pollutants are carried through the ocean by ocean currents, blood flows and seeps through the body carrying oxygen and nutrients to the cells and carrying waste products away, the movement of glaciers on land and water is governed by fluid flow problems.
Fluid dynamics is one of the broadest and most difficult fields of study in all of science.
The equations that fluid dynamicists study can only be solved exactly for some very simple problems. Yet by constantly improving approximations, careful experimentation and ,more recently, the use of computer simulations , many flow problems are now well understood.