Today is the Longest Day of the Year (Photos of the Midnight Sun) June 21 gets the prize as the longest day of the year 2013 in Iceland. Whatâs more, summer seems to be arriving in ReykjavÃ­k. Last night people were waiting to see the midnight sun set, well at midnight in ReykjavÃ­k. The air was calm and clean and so were the people who sat on the shore.
Definition of airfoil. : a body (such as an airplane wing or propeller blade) designed to provide a desired reaction force when in motion relative to the surrounding air.
When an airfoil (or a wing) is moving relative to the air it generates an aerodynamic force, in a rearward direction at an angle with the direction of relative motion. This aerodynamic force is commonly resolved into two components 1  : drag is the force component parallel to the direction of relative motion,orces on an aerofoil. Aerodynamic force is exerted on a body by the air (or some other gas) in which the body is immersed, and is due to the relative motion between the body and the gas. Aerodynamic force arises from two causes: