Chapter 1 - Introduction

Abstract

This chapter provides some of the terminology used in subsequent chapters, provides examples of turbulent flows and their complexity, and introduces some important turbulent-flow characteristics. The chapter starts by addressing the question “What is turbulence?” Then examples of turbulent flow that show its ubiquitous character are given, and the continuum hypothesis is introduced. A number of useful measures have been developed, and a few of the more important ones are introduced: intensity, scale, the energy spectrum and intermittency. The diffusive nature of turbulence is discussed in relation to the gross features of a random motion. Turbulence “simulation” is introduced as the solution of the complete three-dimensional time-dependent Navier-Stokes equations.