15 June
WORLD WIND DAY
15 June is celebrated as World Wind Day.
Wind, breeze, hurricane, zephyr, squall. A phenomenon loved and hated, creating and destroying. How it was received in the past, how to handle it now says Małgorzata Karolus, PhD, Associate Professor.
„Save the date” is a series of articles that have been written to celebrate various unusual holidays. The authors of the presented materials are students, doctoral students and employees of the Faculty of Science and Technology of the University of Silesia.
photo. T. Kawka
MAŁGORZATA KAROLUS, PhD, Associate Professor
Institute of Materials Engineering
According to the definition, the wind is the horizontal or nearly horizontal movement of air relative to the earth’s surface, blowing from areas of higher pressure to areas of lower pressure. The definition can be expanded to include the fact that in middle latitudes, due to the Coriolis force, the wind usually blows parallel to lines of the same pressure (the so-called geostrophic wind). There are about 2000 local wind names worldwide.
A dry definition tells you only this much, but the wind holds many mysteries and possibilities…
Since the dawn of time, the wind and the god of the wind have had their place in mythologies. For example, in Greece, the king of all winds was Aeolus, and perhaps the most famous, Zephyr, brought the west, gentle wind, marking the arrival of spring.
In Slavic mythology, the deity responsible for the winds was Stribog.
In South America, one of the most important gods worshipped among others by the Toltecs and the Maya – Quetzalcoatl (Feathered Serpent), a serpent with the feathers of a bird, was considered the co-creator of the world and the god of wind, sky (symbolised by the feathers) and earth (symbolised by the serpent).
Wind and air have always fascinated people. When the awareness and desire to understand the laws of nature awoke in people, various theories on the construction of the world surrounding us were born.
Thus, already in the second millennium BC, the oldest known philosophical models of the universe were described in the Indian Vedas. It was assumed there that the universe is made up of five elements: Vayu (air ), Ap (water ), Agni (fire ), Prithvi (earth ) and Akash (aether).
In later times, Anaximenes of Miletus (6th century BC) believed that air was the basis of reality. And in the 4th century BC. Aristotle formulated the view that all matter is composed of various mixtures of the four basic elements, which included air, earth, fire, and water.
The oldest wind engine, which converts the energy of the wind into kinetic energy, is the windmill, a wooden or masonry structure equipped with wings that are moved by the force of the wind and that propel the machinery. The oldest windmills appeared in the 9th century in eastern Persia and in the 12th century in Europe. Originally windmills were used to grind grain, but in the 19th century in the Netherlands windmills began to be used to operate pumps that drained polders. Later windmills were used for sawmilling and grinding rocks into aggregates, pressing oil, grinding tobacco and wood into paper, etc.
Today, we associate wind energy primarily with renewable energy sources where electricity is generated by wind turbines. The turbines have three wings each and are located on tall and narrow towers.
Currently, the largest offshore wind farm (wind turbine) in the world is Hornsea One in the North Sea, more than 100 km off the coast of Yorkshire county in the UK. It consists of 174 turbines with a unit capacity of 7 MW, spread over an area of more than 400 km2, and has a total capacity of more than 1.2 GW – enough energy to power more than a million homes.
We should not forget about the use of wind in sports and play.
All the children of the world, on all continents, fly kites on windy days.
Gliding – gliders are aircrafts capable of gliding flight without the use of their own propulsion, which obtain their lifting power in flight due to aerodynamic phenomena occurring on their wings.
Recently, kitesurfing is becoming an increasingly popular water sport – it involves moving across the water on a board with the help of a propeller – a kite.
Last but not least, sailing, the favourite sport of Prof. Karolus, is probably the most popular water sport that uses the energy of the wind.
It is difficult to say with absolute certainty where and how people started sailing on the world’s seas and oceans for the first time. However, there is no doubt that sailing, in its broadest sense, is an important part of the history of navigation and sea trade as well as great geographical discoveries. But the history, development and significance of sailing through the ages is a different story altogether…