What Are the Functions of Wind Speed?

Wind speed functions as a measure for proper sail trim, aircraft performance and aerodynamic design.sail boat image by Kelly Miller from Fotolia.com

There are two kinds of wind speed: relative and ground. Relative wind speed is the speed of the air around you when you are standing still or moving with or against the wind. A balloon moving through the air at 30 miles an hour may experience zero wind speed because the balloon moves with the wind. Ground wind speed is how fast the wind moves over the surface of the Earth. Measuring relative and ground wind speed are important factors when sailing, flying or determining aerodynamics, how an object passes through the air.

Sailing

Sailing means moving both by sail and power. Ships of all sorts measure and rely on wind speed for various aspects of navigation and speed through the water. Wind speed over the water affects currents, and currents affect the vessel's actual speed. If the vessel can make 25 miles an hour and find a prevailing wind at 10 miles an hour, the current can accelerate the speed to between 30 and 35 miles an hour.

Of course, on a sail boat, wind speed is important. Knowing the wind's speed in the travel direction and across the vessel and even into the vessel are needed to set the sails properly for best performance. Even knowing the wind speed in the travel direction is important. Too much sail with the wind at your back can possibly damage the sails, rigging and mast.

Wind speed is vitally important for aircraft takeoffs and landings. Depending on the size of the aircraft and the length of the runway, the wind speed can add to the plane's ability to take off in a shorter distance or land on a shorter runway. The plane's relative wind speed when taking off determines if the proper speed is reached for flight.

Once in the air, wind speed is also critical to calculating the aircraft's range. Flying into the wind reduces the plane's maximum speed and consumes fuel more quickly. Flying with the wind increases the plane's range.

Wind speed is a critical factor when calculating aerodynamic performance. Many designs are calculated to perform best at different wind speeds. Airplanes may fall out of the sky if they fly to slow or be severely damaged by wind speed if traveling too fast. Automobiles and trucks are aerodynamically designed to take full advantage of different wind speeds. Not only is this important for a smooth ride but also for moving air through radiators and brakes for cooling or providing additional down force on the tires for better handling.