Testing Structures Against Hurricane Storm Surge

When hurricanes hit coasts, they bring with them incredible storm surge, which puts buildings right in the middle of ocean waves. To understand how to better protect against those conditions, engineers use facilities like the Directional Wave Basin to create smaller-scale versions of hurricanes. In this Practical Engineering video, Grady visited during a test that compared two identical one-third-scale houses subjected to the same storm conditions–except that one house had an additional foot (3ft at real-scale) of elevation. The results are pretty spectacular.

This isn’t a short video, but it’s well-worth a watch. I think Grady does a great job of explaining why engineers need (admittedly) expensive facilities like this one to help guide both engineering and regulatory decisions. (Video and image credit: Practical Engineering)

Event-Based Recording

High-speed cameras are an amazing tool in fluid dynamics, but they come with a whole host of challenges. The camera and lighting have to be positioned to deal with reflections, the data sets are enormous, and post-processing all that data takes a long time.

Here, researchers experiment instead with studying a flow using an event-based camera, which records information only when and where the brightness changes. The images and videos look strange to our eyes, but, as the authors show, they work nicely for identifying flow features and extracting valuable data. (Video and image credit: D. Sun et al.)

Galloping Bubbles

A buoyant bubble rises until it’s stopped by a wall. What happens, this video asks, if that wall vibrates up and down? If the vibration is large enough, the bubble loses its symmetry and starts to gallop along the wall. Using numerical simulations, the team determined the flow around the bubble. They also demonstrate several possible applications for this behavior: sorting bubbles by size, traversing mazes, and cleaning a surface. (Video and image credit: J. Guan et al.)

#2024gofm #bubbles #experimentalFluidDynamics #fluidDynamics #numericalSimulation #physics #science #vibration

Soaring Through the Pillars of Creation

The Pillars of Creation are an iconic feature nestled within the Eagle Nebula. For decades, the public has admired Hubble’s images of this stellar nursery, and, in this video, we get to fly between the pillars, shifting between Hubble’s visible light imagery and JWST’s infrared views. In visible light, glowing dust obscures the interior of the pillars, drawing our eyes instead to the dusty shapes eroded by the stellar winds of these young stars. In infrared wavelengths, we see further into the pillars, revealing individual stars burning at the ends of the pillars’ fingers. Being able to peer at the same problem through different techniques — here visible and infrared light — reveals more to scientists than either mode can on its own. (Image/video credit: G. Bacon et al.; via Gizmodo)

#experimentalFluidDynamics #fluidDynamics #fluidsAsArt #nebula #physics #science #turbulence

Scientists have long suspected that birds save energy by following a leader — think of the V-shaped flight formation used by geese — but a new study captures that savings directly. The team studied starlings, flying singly or in groups of two or three, in a special wind tunnel. Each bird wore a tiny backpack with sensors and lights that captured its motion and helped researchers identify it individually in videos. And, using before and after metabolic measurements, the researchers could pin down exactly how much energy each bird used when flying.

They found that birds who spent most of the flight in a “follower” position used up to 25% less energy than they did when flying solo. That’s a major incentive to follow someone else. Interestingly, they also found that the most efficient solo fliers were the birds most likely to take on the “leader” position. The team notes that these “leaders” tend to use a lower wing-flapping frequency, but a full explanation of how they save energy will require a follow-up study. (Image credit: R. Gissler and S. Hao; research credit: S. Friman et al.; via Physics World)

https://fyfluiddynamics.com/2024/07/saving-energy-by-following-a-leader/

#biology #birds #drafting #experimentalFluidDynamics #flappingFlight #fluidDynamics #physics #science #windTunnelTesting