Flow

Flow is a movement of substance, energy (field), and information within an engineering system.

Overview

Flow refers to the movement of material objects (substances and energy), or information through space. What matters is its presence and motion within the engineering system under consideration, although it may also partially occur in the supersystem.

Dynamics (movement through space) is a key feature of flow. It exists as long as the “flowing” element is in motion – if it stops, the flow ceases (disappears), even though all of its components remain within the system. This means that flow can “disappear” from the system without removing any of its components.

Flows in the system are analyzed during the flow analysis, which is performed after the function analysis. There are three types of flows analyzed:
1. substance flow,
2. energy flow, and
3. information flow.

Categories of flows

There are four categories of flows. They are the following:

Useful flow is a flow whose object (substance, energy, or information) performs a useful function or is an object of a useful function.

Harmful flow is a flow whose object (substance, energy, or information) performs a harmful function.

Wasted flow is a flow that is characterized by losses of substance, energy, or information.

Neutral flow is a flow that has an irrelevant or insignificant influence on the engineering system.