HOW CAN WE USE WIND POWER???
Years ago people used wind only for running windmills, but today we have large wind power plants with triple-blade rotors. These power plants make electricity which can be used for residential as well as industrial purposes. The power of wind can be observed in nature too-it forms huge rocky arches or impressive sand dunes. We can feel it even while sailing, mainly while sailing at 'high wind'. The importance of wind is also felt when sailors have to come to an involuntary stop in the windless areas of the subtropical calms.
HOW DO WINDMILLS WORK???
Windmills are machines that are driven by wind. Their blades have slightly diagonal surfaces. If the wind hits them from front, they deflect it to the side and in this way convert the wind pressure in a rotary movement. Initially, millers had to set the blades themselves in such a way that the wind came on to them from the front. The rotary movement of the blades gets transferred to the milling stones inside the mill through cogwheels. Windmills were traditionally used to mill corn to make flour and grate spices. They also acted as drive for oil presses and sawmills.
WHY DO LARGE WIND WHEELS HAVE THREE ROTOR BLADES???
When compared with the two-blade rotors, the three-blade rotors are more stable and quieter. The disadvantage of the two-blade rotors is that they need a special ‘wobble’ motor to prevent the severe collision when the rotor passes the tower. When the rotor blade is on top, the wind presses against it with full force and bends it. At the same time, the opposite rotor blade is in front of the tower. Thus, it cannot counteract the high pressure at the upper blade which leads to a strong jerk which is compensated by the wobble motor. This problem does not occur in three-blade rotors because the blades are never exactly opposite to one another. In addition, the three blades form a kind of disc for the flowing wind and are hardly prone to faults.
WHAT DOES ‘SAILING AT HIGH WIND’ MEANS???
When we sail at ‘high wind’, we travel-as far as possible-against the wind. The wind, thus comes diagonally from the front. The propulsion takes place when the wind sweeps quickly past the sails, which are possibly set up in the middle of the boat. In contrast , if the boat travels ‘before the wind’; the sails are diagonal to the boat. The wind comes from behind, blows in to the sails, and pushes the boat forwards.
DID YOU KNOW THAT???
•IN 1830,THERE WAS A LOCOMOTIVE WITH SAIL DRIVE. IT TRAVELLED IN USA BETWEEN BALTIMORE AND THE RIVER OHIO.
•WINDMILLS DID NOT ORIGINATE IN THE NETHERLANDS AS COMMONLY BELIEVED?THEY WERE FIRST INVENTED IN PERSIA.
•SAILING ‘BEFORE THE WIND’ IS THE FASTEST TYPE OF SAILING AND NOT SAILING AT ‘HIGH WIND’.