2019.08.26 - How do wave pools work?
How do wave pools work?
We don’t go to the beach just to relax, but we also like fun activities as far as it doesn’t have serious risks. Wave pools were made to imitate the waving of the sea without the real life risks. When did it all start, where are they now and how do they work?
The first wave pool in Hungary, which was a curiosity back then, was made in 1925 in the swimming pool of Csillaghegy. The next one was made two years later in 1927 in the Gellért bath, and it was followed by two more ten years later, one of which is located in Palatinus and the other one in Hajdúszoboszló. The following news segment was written about the opening of the waving pool in Gellért bath.
Nowadays most of the bigger baths have one. Only the extraordinary ones make it into the news, one of which was the one which could imitate the sound of the sea almost perfectly. Obviously the one with the biggest area and the one with the tallest-wave-making machine made it into the news. In Las Vegas there is one with sand on its “bank” which really creates the illusion of a real beach. Unfortunately there isn’t one like that in Hungary, but there are many regular ones. Other places created surf parks where people can try to stay on their boards while riding an artificial wave.
Is it dangerous?
Wave pools probably seem more dangerous from the outside. Waves raise you which can be scary, but they put you back safely to the same spot just like regular waves. While having fun in the waves can be very dangerous in the sea because of the opportunity of colliding with rocks, the plain bottom of the pool can’t really hurt you. Since everyone sways in the same pace, you can’t really collide with other people either. Wave pools can be dangerous especially for children playing alone. The waves could capsize them and they might try to breath in the wrong time. If the pool creates big waves, children can only be there with parental guidance even if they can swim well. Naturally this applies to real waves too.
How does it work?
Making artificial waves is not too complicated. There are four ways to form them.
1) The most common way is that the mechanical movement of a piston creates the waves. They move a cuboid shaped piston in a cuboid shaped concrete pit with electric motors, which makes the water in the pool move up and down. The height of the waves can even be 1-1.5 meters. Its pace is usually 12-15 waves per minute. The disadvantage of this method is that it takes a lot of electric energy. For example the output of a wave making machine for a 600 m2 pool can be 60 kW, which is equal to the maximum output of an 80-horsepower car.
2) Less energy is needed while using a wave ball, which was developed in the ‘90s. The essence of this method is that they put a giant ball in the water, which is moved up and down by an electric motor while making waves. The system can make really big waves if the pool has vertical walls, since the waves can rebound and combine with other waves. If the walls aren’t vertical there is not reflection occurring. The beauty of this method is that it can be installed anytime, even years after the pool was made.
3) Pneumatic wave pools exist too. These are similar to the first ones, but this time water is moved by high-output vacuum pumps, which supersede the water from a chamber, then other huge pumps make the water flow back.
4) The essence of flooding is that they let a gigantic amount of water into the pool in a short period of time, which rushes through the surface of the water. Its working mechanism is the following: high-output pumps suck the water up to a high reservoir, and then they open up the sluice of it, which allows the huge amount of water to flow back, creating a wave. Unfortunately this method is energy-intensive and expensive.