ABSTRACT
In Nature, most practical applications are associated with turbulent flows. These include river flows, wind flows around land forms (e.g. hills, mountains), oceanwaves. In engineering applications, many fluid flows are also turbulent: e.g., spillway flows, wind flows between buildings in a city. The fluid involved may be gas or liquid. In external flows, some relative motion occurs between an object and a large mass of fluid: e.g., the wind flow around an airship (Fig. 1.1). Internal flows include pipeline systems, and irrigation water channel. The flow may be steady or unsteady: e.g., a plane at take off. Whilemany applications involve turbulent flows, laminar flows occur in medical engineering (e.g. blood flows), slow-moving landslides and lubrication.
