CONSERVATIVE LAW GOVERNING EQUATIONS IN FLUID MECHANICS

Abstract

The objective of this article is to show how to derive those conservative laws in fluid mechanics; mass, momentum and energy conservation.  By the fact that mass in a system is always constant, we could gain the mass conservation equation.  In the meantime, by the 2^nd Newton’s law, we can deduce the momentum conservation equations.  Finally, by using the fact, from the 1^st law of thermodynamics, that rate of energy changed in a control volume equals to rate of heat combined with rate of work changed in and out of the control volume.