INTRODUCTION: BASIC EQUATION IN FLUID MECHANICS
Derivations of the basic equations of fluid mechanics are very
necessary because they fulfill the requirements for the broadest applicability
in areas of science and engineering. Fluid mechanics considerations are applied
in many fields, especially in engineering. Concerning the formulation of the
basic equations of fluids mechanics, it is easy to formulate the conservation
equations for mass, momentum, energy and chemical species for a fluid element.
The derivations of basic equations can be represented in an easily
comprehensible way and it is possible to build up the derivations upon the
basic knowledge of physics. Derivations of the basic equations are usually
followed by transformation considerations whose aim is to derive local
formulations of the conservation equations and to introduce field quantities into
the mathematical representations.
The objective of
the derivations is to formulate the conservation laws for mass, momentum,
energy and chemical species in such a way that they can be applied to all the
flow problems that occur. Common equations in fluid mechanics are Bernoulli
equation. The equation is a statement of the conservation of energy in a form
useful for solving problems involving fluids. For non-viscous, incompressible
fluid in steady flow, the sum of pressure, potential and kinetic energies per
unit volume is constant at any point. Then, the common equation that used in
fluid mechanics are Navier-Stokes equations which are the motion of a non-
turbulent, Newtonian fluid is governed by that equation. The equation can be
used to model turbulent flow, where the fluid parameters are interpreted as
time-averaged values.in that case, there
are so many equations that have been derived to make a formula which can make
life easier in doing everyday works.