4.5: Fluid Principles

There are a few principles about the behavior of fluids that we will discuss in this section. We will start with the oldest and work towards the more recent. Notice as we do so that there is a level of increasing complexity as more and more properties of the fluid are considered as science progresses. Also, that sometimes relationships are discovered which are subsets of other relationships that have not yet been discovered. For example, you will see that Archimede's Principle can be viewed as an application of Newton's Laws of Motion. But Archimede's Principle precedes the formulate of Newton's Laws by nearly 2000 years! Likewise, you should be able to see how Pascal's Principle is an application of the Bernoulli Principle. There are other, more complex relationships beyond the scope of this class which incorporate more and more variables into how we understand fluid mechanics: The Bernoulli equation, which we hint at, the Euler equations, and the Navier-Stokes equations for example.

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