Notes - Chapter 3 Summary

The following notes are taken from Wind Turbine Technology by Ahmad Hemami.

• Any object in the wind stream subject to a force from wind
• Force an object depends on the form and size of the object
• Force can result in torque
• Force can be measured in pounds
• Torque in foot-pounds
• Forces are represented with vectors
• force on a plate from wind depends on angle between plate and wind direction called angle of attack
• aerodynamic forces include
• drag
• drag coefficient is ratio of drag force to aerodynamic force
• lift
• ratio of lift force to aerodynamic force
• airfoil is a long thin object with a large lift coefficient but a small drag coefficient
• leading edge confronts air
• trailing edge leaves air
• chord the width between the leading edge and trailing edge that is larger than the average thickness
• chord line is the straight line between leading and trailing edge
• gradual curves round leading edge, sharp trailing edge
• low thickness to chord ratio

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