Basic Equations

To analysis of any fluid problem, the knowledge of the basic laws governing the fluid flows is required. The basic laws, applicable to any fluid flow, are:

1. Conservation of mass. (Continuity)

2. Linear momentum. ( Newton 's second law of motion)

3. Conservation of energy (First law of Thermodynamics)

Besides these governing equations, we need the state relations like and appropriate boundary conditions at solid surface, interfaces, inlets and exits. Note that all basic laws are not always required to any one problem. These basic laws, as similar in solid mechanics and thermodynamics, are to be reformulated in suitable forms so that they can be easily applied to solve wide variety of fluid problems.