#pathlines

[fuckyeahfluiddynamics]

Glacier Timelines

Over the past 150 years, Switzerland's glaciers have retreated up the alpine slopes, eaten away by warming temperatures induced by industrialization. But such changes can be difficult for people to visualize, so artist Fabian Oefner set out to make these changes more comprehensible. (Image credit: F. Oefner; video credit: Google Arts and Culture) Read the full article

[fuckyeahfluiddynamics]

Ciliary Pathlines

For tiny creatures, swimming through water requires techniques very different than ours. Many, like this sea urchin larva, use hair-like cilia that they beat to push fluid near their bodies. The flows generated this way are beautiful and complex. (Image credit: B. Shrestha et al.) Read the full article

[fuckyeahfluiddynamics]

Playing With Water in 2D Containers

Once again Steve Mould is putting his prototyping skills to use to work out what goes on inside tricky containers. Here he looks at a "magic" wizard's cup where -- like the assassin's teapot -- cleverly placed holes in the side of the cup can block or allow air's escape. In the wizard's cup this lets the wizard refill the cup at will. (Video credit: S. Mould) Read the full article

[fuckyeahfluiddynamics]

Corralling Corals

So much of fluid dynamics is seeking patterns. Shown here are two sets of patterns, each created by a different species of coral larvae.  (Image credit: G. Juarez and D. Gysbers) Read the full article

[fuckyeahfluiddynamics]

Paddling Pathlines

Rainbow lines cut through the darkness in photographer Stephen Orlando's images of a kayak in motion. Equipped with an LED-lined paddle, Olympic kayaker Adam van Koeverden paddled along the waterfront while Orlando took long exposure photographs. (Image credit: S. Orlando)

[fuckyeahfluiddynamics]

If you’ve ever gone into the woods on a windy day, you know that conditions there are drastically different than in the open. To blowing wind, trees of different sizes act like enormous roughness that disturbs the flow. Inside the canopy, flows can become incredibly complicated and many of the common techniques used by researchers no longer hold. 

You can get a sense for this complexity with the second image above, which visualizes data from a wind tunnel experiment. The gray blocks represent roughness elements -- the trees of this wind-tunnel-scale forest -- and the large, blue arrow shows the direction of the flow. The thin colored lines show the paths taken by particles in the flow. The lines’ colors indicate what height the trajectory began at. 

Notice how the blue and purple lines are relatively straight and oriented in the direction of the flow. This indicates that the flow here is relatively steady and uncomplicated. At the lower heights, though, especially in the green and yellow regions, the pathlines are far more twisted and complex. The flow here is turbulent, and the particles’ trajectories don’t necessarily correlate at all to the winds higher up. (Image credit: T. Japyassu and R. Shnapp et al.; research credit: R. Shnapp et al.; submitted  by Ron S.)

[fuckyeahfluiddynamics]

In industry, tanks are often agitated or stirred to mix different elements. The goal is to create a laminar but chaotic flow field throughout the mixture. Introducing particles to such a system reveals that things are not quite as chaotic as they might seem. The photographs above show the pathlines of various large, glowing particles initially poured into the tank from above. Over time, the particles scatter off of structures in the mixed sections of the tank and end up trapped in vortex tubes that form above and below the agitator. Once trapped in the vortex tube, the particles follow helical paths inside the tube, creating patterns like those seen in the lower two photos. (Image and research credit: S. Wang et al., 1, 2, 3)

[breathe-expression]

“No sense in trying to stop

I couldn't stomach the drop

When you were bending

I was breaking

We're just twisting the plot”