Chapter 17. Introduction to Oscillations

Many systems exhibit intriguing oscillations over time. You will probably recall becoming intrigued the first time you felt the rhythmic beating of your heart, and perhaps you have become intrigued by the rhythmic crashing of ocean waves at the seashore. These and other oscillatory systems are fascinating to observe. But they are difficult to understand. A basic understanding of oscillations is useful for professionals in many fields. For example, cycles in the national economy challenge economic planners; cycles in animal and plant populations challenge environmental managers; and cycles in insulin secretion challenge biomedical scientists.

This chapter, and the following two chapters, demonstrate how models may be used to improve our understanding of oscillatory behavior. This chapter begins with the flower and sales models from Chapter 6. The opening example shows oscillations imposed by outside forces. The remaining examples are more interesting. They describe oscillations that arise from inside the flower system and the sales system. The introductory examples set the stage for the more detailed examples. Oscillations in predator and prey populations are described in Chapter 18; oscillations in aluminum production are described in Chapter 19. You'll see from these concrete examples that system dynamics is a powerful tool to help us look "inside a system" for an explanation of oscillatory behavior.