ABSTRACT

In this chapter, the basic characteristics of turbulence are introduced. Some turbulent flow properties are described and discussed. Some basic equations are developed.

1 PRESENTATION

Turbulence describes a flowmotion characterised by an unpredictable, pseudo-random behaviour, some very-strong mixing properties and a broad spectrum of time and length scales (Lesieur 1994). Bradshaw (1971, p. 17) added: “turbulence is a three-dimensional time-dependent motion in which vortex stretching causes velocity fluctuations to spread to all wavelengths between a minimum determined by viscous forces and a maximum determined by the boundary conditions of the flow’’.