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About this Article
Written by: Christian Lee
Written on: September 12th, 2016
Tags: lifestyle, sports & recreation, mechanical engineering, aerospace engineering, water
Thumbnail by: Josh Dean/Bloomberg
About the Author
Christian Lee was a student at the University of Southern California at the time this article was written.
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Volume XVIII Issue II > The Future of Surfing
Surfing. When you hear that word, what comes to mind? You might think of a guy on a surfboard speeding down the face of a monstrous sixty-foot wave, an aged Hawaiian man paddling into the sunset, a smiling Bethany Hamilton holding her surfboard, or maybe even the Beach Boys. The general sentiment towards surfing is that it’s positive and laid-back.

Introduction

Surfing was invented by the Hawaiians centuries ago and was the sport of kings. To the Hawaiians, surfing was not only a sport, but also profoundly spiritual. Riding waves was about connecting with the ocean, not controlling it. The first outsiders to encounter Hawaiians were the British in 1777. They were stunned by the sport and its ability to make people so happy. When James Cook watched a native man surfing, he said, “I could not help concluding that this man felt the most supreme pleasure.” Centuries later, the estimated twenty-three million surfers worldwide today have continued that royal Hawaiian legacy and experience the joy associated with it [1]. A unique characteristic of surfing is its relationship with nature; a surfer needs to learn to work with the ocean, and its waves, in harmony.
Every surfer dreams of the perfect wave – a wave that has the right shape, size, consistency, and length of ride. This wave is very difficult to find. Yet, after ten years of working with a University of Southern California aerospace engineer, professional surfer Kelly Slater has engineered the perfect artificial wave [2]. Millions of people are now thinking about what the future of surfing will look like and how artificial waves will shape it.

The Engineering Behind Artificial Waves

Naturally occurring ocean waves are unpredictable and constantly changing. No two waves are the same, requiring surfers to constantly adapt to their conditions – a task difficult for many surfers. However, surf simulators, first invented in the early nineties, allow anyone to surf by pumping out consistent and identical waves[2]. Surf simulators are created in pools and emulate the natural processes of ocean waves through clever engineering.
The main principle behind surf simulators is “hydraulic jump.” Hydraulic jump is a naturally occurring phenomenon in open channels of water, such as rivers. It happens when a rapidly moving flow of water meets a still portion of the water. The rapid water flow slows down quickly, converting its kinetic energy into potential energy that causes the water to rise; this creates hydraulic jump. The speed of the rapid water is very important. The minimum speed required to create a hydraulic jump is called the “critical speed” – if the rapid water isn’t flowing at critical speed, a jump isn’t possible. A simple example of hydraulic jump can be seen in a sink. f there is already some water in the sink and you turn the sink on, the stream of water from the faucet will cause a circular wave – or hydraulic jump – to spread out (Fig. 1). To use hydraulic jump to create a wave that someone can be propelled on, an object is placed under the flowing water to direct the water upwards [3]. The redirected water flow is the wave itself and contains potential energy that, if powerful enough, can push a person on a board. The shape and placement of the object affects the direction of the water flow, changing the angle the wave would push a surfer – diagonally to the left or diagonally to the right. Engineers can manipulate the object to control different aspects of the wave created from hydraulic jump. For example, to create a more challenging wave for its users, the object can be made taller and steeper, or to create a wave that breaks in a certain direction (direction of the water flow), the object can be angled in such a way to have the gradual peeling effect that will be described in the next section. Despite its novel capabilities, his technology has only been used by novice surfers It has been insufficient for and unsatisfying to experienced surfers.
Kilfiger/Wikipedia
Fi​gure 1: An example of hydraulic jump from a sink faucet.

The Perfect Wave

The technology created using hydraulic jump has progressed over the years into systems that produced Kelly Slater’s perfect wave. Now, generated waves are created with a technology called “hydrodynamic Wavefoil.” The hydrodynamic Wavefoil is an advanced version of the object that was placed decades ago under hydraulic jump systems to create wave pools. It is shaped like a snowplow and set on an underwater track powered by a motor. The track and motor are new additions to the artificial wave system from the original wave pool design in the sixties. As the rapid water flow moves towards the shore of the lake, the underwater track pulls the hydrodynamic Wavefoil away from the shore, opposite of the water flow. This is modeled after the formation of ocean waves. In an ocean, as the water moves towards the shore, the water at the bottom of the wave flows the opposite way. In a lake, when the hydrodynamic Wavefoil is pulled in the opposite direction as the above water flow, the water molecules hit it and bounce off in a circular motion, mimicking what happens in real ocean waves. When the water molecules spin, it causes a hydraulic jump on the surface of the lake, forming a wave [5].
Simply put, the water on the bottom of the lake is displaced by the snowplow-looking hydrodynamic Wavefoil and pushed up to make a wave. The angle of the hydrodynamic Wavefoil is set in such a way to create the perfect, barreled shape that breaks gradually and smoothly (see Fig. 2). When a wave breaks, its potential energy from the hydraulic jump reaches a critical point and is converted back into turbulent kinetic energy that “breaks” to make white water. A wave that is not smooth nor gradual doesn’t break from left to right or right to left, but altogether or inconsistently. This type of wave cannot be surfed, and is undesirable to many surfers.
Josh Dean/Bloomberg
Figure​ 2: Kelly Slater riding his perfect wave.

Implications of the Perfect Wave

On December 5, 2015, Kelly Slater rode the first perfect wave generated by a machine with the push of just a few buttons. Ecstatic, he proclaimed in a publicly released video that “this is the best man-made wave ever made. No doubt about it.” Within a week, the video had 9 million views from people all over the world – the perfect wave that the surfing community had been dreaming of was finally created. While the video opened the world up to an entire new realm of surfing, it still isn’t clear exactly what direction this machine will go. Six months after the video’s release, the World Surfing League bought out Kelly Slater’s perfect wave machine company for use by professional surfers [6]. However, no one is sure yet on how it will be used on a commercial scale. What implications will the perfect, man-made wave have on the world of surfing?
The perfect wave has the potential to have a negative effect on surfing. The origins of surfing from Hawaii are spiritual and were centered around communing with the ocean instead of harnessing or controlling waves. Many surfers have raised concerns because the perfect wave takes away the changing conditions of waves. Surfers are required to adapt to what is in front of them and waves can be unpredictable as they are completely reliant on nature. Professional competitions are heavily affected by the conditions of the ocean that day, even down to the hour. In the future, even if the World Surfing League doesn’t mass-produce the artificial perfect wave, the technology could be sold to other companies or copied to commercialize what Kelly Slater created. On the artificial perfect wave in an artificial pool, people no longer need to learn how to work with the elements of nature or experience the volatile ocean conditions. This places the mystique and uniqueness of surfing that many hold so dearly in jeopardy.
On the other hand, there are positive implications that the perfect wave could have on the world of surfing. To millions of people, surfing is a sport that they’ve only seen in movies and could never dream of actually trying. Artificial waves could bring surfing to landlocked people and allow them to experience what it’s like to be on a wave. Even though surfing an artificial wave isn’t the same as surfing in an ocean, more people could enjoy it and perhaps even prefer artificial over natural waves. Furthermore, artificial waves could be used as a practice tool for surfers, allowing them to work up toward natural, more unpredictable waves. Surfing in the ocean is difficult, but the artificial wave’s consistency could act as a less-intimidating avenue into surfing. These artificial waves form at the same spot every time and break at the same speed-an advantage that could ignite a surfing revolution.

Conclusion

Undoubtedly, the perfect wave is cool. There are mixed reactions to its effects on the future of surfing, but the reaction to Kelly Slater’s initial footage of his perfect wave was overwhelmingly positive. All of this was made possible by the collective minds of surfers and engineers alike. The engineering behind artificial waves was the product of several decades of work and development, ending up in a remarkable result with both strengths and weaknesses. The impacts of this new technology on the surfing world are still uncertain, but they are indeed exciting.

References

[4] A. Toepperwein, "Making Waves - Engineering a Hydraulic Jump," in Surf’s up – indoor
wave engineering - product design show, 2011. [Online]. Available:
http://www.engineeri​ng.com/Videos/Produc​tDesignChannel/Video​Id/2679/Surfs-Up-Ind​oor
Wave-Engineering.asp​x. Accessed: Sep. 6, 2016.
[5] "How to engineer surfing waves- Boston commons high tech network," in Boston Commons, Boston Comons High Tech Network, 2016. [Online]. Available: http://bostoncommons​.net/how-to-engineer​-surfing-waves/. Accessed: Sep. 6, 2016
[6] J.Dean, "Kelly Slater built the perfect wave. Can he sell it to the world?," in Bloomberg, Bloomberg.com, 2016. [Online]. Available: http://www.bloomberg​.com/features/2016-k​ellyslater-wave-pool​/. Accessed: Sep. 6, 2016.

References

    • [1] A. Foremen, "A short history of surfing," in Wall Street Journal, wsj.com, 2015. [Online]. Available: http://www.wsj.com/a​rticles/a-short-hist​ory-of-surfing-14394​79278. Accessed: Sep. 6, 2016.
    • [2] J. Mozingo, "Is Kelly Slater's artificial wave in the future of surfing?." in phys.org, 2016. [Online]. Available: http://phys.org/news​/2016-05-kelly-slate​r-artificial-future-​surfing.html. Accessed: Sep. 6, 2016.
    • [3] D. Alpher, "Wave machines - technology, engineering, and surfing's future," in American Wave Machines, Surf Park Central, 2012. [Online]. Available: http://www.surfparkc​entral.com/wave-mach​ines-technology-engi​neering-and-surfings​-future/. Accessed: Sep. 6, 2016.