Essay On Airfoil

Airfoil is a stream line body, or a lifting surface, of simple shape that provides sufficient lift and considerably less drag at small angles of attack. An Airfoil is considered to be a two dimensional body because its geometric sections normal to span do not change. As the air flows over the airfoil, the velocity on the upper surface is more than the free stream velocity and the velocity on the lower surface is less than the free stream velocity. Hence by Bernoulli’s theorem Pressure on the lower surface is more than the upper surface and a perpendicular force is created in upward direction which is known as Lift. Modern airfoils have evolved after years of theoretical and experimental research. The design philosophy of an airfoil is useful in many other disciplines that use Newtonian fluids.

3.7.2 Geometry of an Airfoil

Figure 3.5: Geometry of an Airfoil [3]

1. Lift Coefficient (CL)

Is a dimensionless coefficient that relates the lift generated by airfoil, the dynamic pressure of the fluid flow around airfoil, and a

So darrieus turbine is very much useful in remote villages for production of cheap electricity where still electricity is not still reached. Darrieus turbine is operated on a lift generated by the aero foil so efficiency of the darrieus turbine is more compare to the drag driven turbine. They have some advantages over axial flow turbines: they are having High co-efficient of performance, they can easily drive a generator above install it , they do not need to yaw and blades are untwisted and of uniform cross section, so they can be extruded at low cost. So, it’s a best way to generate power by darrieus turbine from low wind flow. Darrieus turbine can also be used to generate electrical power for household applications. To operate water pumps, charging batteries, powering telecommunications and several other power