Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

FIG. 10.2. Tower Windmill, Bidston, Wirral, UK. circa 1875.
pivoted slats for control. The US wind-pump made use of a large number of sheet-metal
sails (Lynette and Gipe 1998). The remarkable revival of interest in modern wind
powered machines appears to have started in the 1970s because of the so-called fuel
crisis. A most interesting brief history of wind turbine design is given by Eggleston and
Stoddard (1987). Their focus of attention was the use of wind power for generating
electrical energy rather than mechanical energy. A rather more detailed history of the
engineering development of windmills from the earliest times leading to the introduction
of the first wind turbines is given by Shepherd (1998).
Types of wind turbine
Wind Turbines 325
Wind turbines fall into two main categories, those that depend upon aerodynamic
drag to drive them (i.e. old style windmills) and those that depend upon aerodynamic