2.1. Classification of Fluids.
Fluids are classified as either compressible, gases; or incompressible, liquids. Liquids are compressible to a very small degree, but no significant error results in most engineering calculations if incompressibility is assumed. Gases are compressible, a feature that must be recognized from the fluid mechanics standpoint. However, the agricultural processing engineer Will generally be working with air at such low pressures that compressibility will not be a significant factor.
Consequently, compressibility, the change of specific weight with pressure, is not considered in this chapter.