Beneath the Surf

A surfer duck-dives beneath a passing wave in this image from photographer John Barton. I always love seeing big waves from this underwater perspective.  (Image credit: J. Barton/OPOTY; via Colossal) Read the full article

Paris 2024: Gunwale Bobbing

In the Olympics, you won't see anyone win a rowing event without a paddle, but it turns out that you don't really need one for a canoe or paddleboard. How can you get around when you've lost your paddle? You stand up on one end and start bobbing. This is known as gunwale (pronounced gunnel) bobbing, and it's pretty impressively effective!  (Image credit: top - R. Chisu; others - G. Benham et al.; research credit: G. Benham et al.; via APS Physics; submitted by Kam-Yung Soh) See more of our past and ongoing Olympic coverage here. Read the full article

Swarm of Surfers

Self-propelled objects can form fascinating patterns. Here, researchers investigate how small plastic "surfers" move on a vibrating fluid.  (Image and research credit: I. Ho et al.; via APS Physics) Read the full article

Surf's Up!

Inspired by honeybees and their ability to surf on capillary waves of their own making, researchers have developed SurferBot, a low-cost, untethered, vibration-driven surf robot. (Image and submission credit: D. Harris; research credit: E. Rhee et al.) Read the full article

Tokyo 2020: Surf Physics

Surfing is making its Olympic debut this year with a shortboard competition held at Shidashita Beach, with the event's timing determined by weather and wave quality. The fluid dynamics involved in surfing could easily fill their own series of posts, so we'll just scratch the surface here.  (Image credit: B. Selway; video credit: TED-Ed; see also M. Grissom and Science Connected) Read the full article

Filmmaker Chris Bryan captures surfer Kipp Caddy as he rides an enormous wave in "Dancing With Danger." (Image and video credit: C. Bryan)

What happens to a honeybee that gets stuck in the water? It surfs its way to land! (Image and research credit: C. Roh and M. Gharib; via NYTimes; submitted by Kam-Yung Soh)

As a follow-up to the recent waves post, reader robotslenderman asks:

I wasn’t able to find an equivalent breaking wave version of that dyed wave -- side note: readers with flumes, please feel free to make one and share it! -- but here’s an undyed breaking wave for our reference.

Waves break, or get that white, frothy look, when they reach shallower water. In the previous post, the waves we saw were effectively deep-water waves, so they didn’t change in height as they rolled across the tank. Here there’s an incline to simulate a beach, which causes the water to slow down and steepen. That forms the characteristic curl of a plunging breaker, seen here.

At the beach, a wave runs out of water to pass through and all the energy that wave was carrying has to go somewhere. Some is lost as heat, some turns into the sound of that classic crashing wave, and a lot of it gets dissipated as turbulence that pushes us, sand, shells, and anything else its way.

As for why we can ride waves, there’s some special physics at play when it comes to surfing. To catch a wave, a surfer has to paddle hard to get up to the wave’s speed just as it reaches them. Too slow and the wave will just pass them by, leaving them bobbing more or less in place. (Image credit: T. Shand, source)

Many of us who grew up visiting water parks instead of ocean beaches have spent time bobbing in a wave pool. They’ve been around for decades. But a new generation of wave pools are aiming for a different goal: the perfect surf wave. One of the foremost current facilities is Kelly Slater’s Surf Ranch, shown above. Here a hydrofoil (draped in blue tarps on the left) is pulled along an artificial lagoon to create dozens of wave profiles, all engineered to give surfers a long ride on the perfect solitary wave.

Other facilities, like the surf ranch used by USA Surfing in Waco, Texas, design their waves with different goals in mind. The Waco wave pool uses air pressure to drive their waves, and aims for a larger quantity of shorter waves. They’re designed to help young surfers practice skills they’re working on, and to give them a place where they can experience waves like those they’ll face in the upcoming 2020 Olympics in Tokyo. (Image credit: R. Young/WIRED; CNet, source; submitted by Lionel V.)

This short film for the 2016 Gallery of Fluid Motion features Montana State University students experiencing fluid dynamics in the classroom and in their daily lives. As in her previous film (which we deconstructed), Shanon Reckinger aims to illustrate some of our everyday interactions with fluids. This time identifying individual phenomena is left as an exercise for the viewer, but there are hints hidden in the classroom scenes. How many can you catch? I’ve labeled some of the ones I noticed in the tags. (Video credit: S. Reckinger et al.)

Birds can be incredibly clever about using their surroundings to enhance their flight. Pelicans will even surf! As a line of waves rolls toward shore, it pushes a small updraft ahead of it -- just like a line of mountains creates a windy updraft. Pelicans save energy by riding the updraft just like a surfer would ride the swell. Once the wave breaks, the air and water become turbulent and less useful, so the pelican cuts away to find his next ride. (Image and submission credit: N. Yarvin, source)

Inside Science has a new documentary all about fluid dynamics! It features interviews with five researchers about current work ranging from the physics of surfing to the spreading of diseases. Penguins, sharks, archer fish, 3D printing, and influenza all make an appearance (seriously, fluid dynamics has everything, guys). If you’d like to learn more about some of these topics, I’ve touched on several of them before, including icing, penguin physics, shark skin, archer fish, and disease transmission via droplets.  (Video credit: Inside Science/AIP)