# Category Archives for **Basic Principles**

## Piping – Moody Friction Factor

The factor of proportionality in the previous equations is called the Moody friction factor and is determined from the Moody resistance diagram shown in Figure 8-1. The friction factor is sometimes expressed in terms of the Fanning friction factor, which … Continue reading

## Piping – Darcy's Equation

This equation, which is also sometimes called the Weisbach equation or the Darcy-Weisbach equation, states that the friction head loss between two points in a completely filled, circular cross section pipe is proportional to the velocity head and the length … Continue reading

## Piping – Bernoulli's Theorem

It is customary to express the energy contained in a fluid in terms of the potential energy contained in an equivalent height or “head” of a column of the fluid. Using this convention, Bernoulli’s theorem breaks down the total energy … Continue reading

## Piping – Flow Regimes

Flow regimes describe the nature of fluid flow. There are two basic flow regimes for flow of a single-phase fluid: laminar flow and turbulent flow. Laminar flow is characterized by little mixing of the flowing fluid and a parabolic velocity … Continue reading

## Piping – Reynolds Number

The Reynolds number is a dimensionless parameter that relates the ratio of inertial forces to viscous forces. It can be expressed by the following general equation: The Reynolds number can be expressed in more convenient terms. For liquids, the equation … Continue reading