A home has a domestic water system that supplies water for drinking, cooking, washing, and operating toilets. It also has a house drain system for collecting waste water and sending it to a treatment system, either an individual septic system or a community sewage treatment plant. Cities and most towns have potable water supply systems that pump water from wells or reservoirs and distribute the water to residences, businesses, etc. These systems must also provide emergency water supplies for fighting fires. Natural gas fuel is supplied to homes, factories and power plants by a national network connecting thousands of wells to the consumers of gaseous fuel.
Fuel oil is pumped from wells to storage tanks and then pipelined to a refinery for processing.
Similar systems carry heat or cold in transportation vehicles. In steam power plants, steam and water flow through a cycle that converts some of the heat from the fuel to mechanical work. As you read this paragraph, your heart is pumping blood throughout a very complex system that supplies the cells in your body with oxygen and nutrients while simultaneously removing waste products. Clearly, both we and our society depend upon the successful functioning of many fluid systems for our physical support. This chapter is concerned with the problem of making fluids move through systems in a desired way.