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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.