Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
Turning Sand Into a Fluid
Pumping air through a bed of sand can make the grains behave just like a liquid. This process is called fluidization. Air introduced at the bottom of the bed forces its way upward through the sand grains. With a high flow rate, the space between sand grains gets larger, eventually reaching a point where the…
Jupiter’s Atmosphere
Jupiter’s atmosphere is fascinatingly complex and stunningly beautiful. This close-up from the Juno spacecraft shows a region called STB Spectre, located in Jupiter’s South Temperate Belt. The bluish area to the right is a long-lived storm that’s bordering on very different atmospheric conditions to the left. Shear from these storms moving past one another creates…
Galapagos Week: Sea Turtles
It’s easy to imagine sea turtles as slow and awkward given our familiarity with their terrestrial cousins, tortoises, but this could hardly be further from the truth. There are currently seven living species of sea turtles and all use a mode of locomotion known as aquatic flight. As the name suggests, swimming sea turtles share…
Galapagos Week: Diving Birds
One of my favorite things to do while we were sailing along the Galapagos was watching the blue-footed boobies hunt. Like the gannets shown above, boobies are plunge divers. They circle overhead until they spot their prey, then they fold their wings and dive headfirst into the water, impacting at speeds of more than 20 m/s…
Galapagos Week: Lava Flows
The Galapagos islands are geologically similar to the Hawaiian islands; both are archipelagos that were born and continue to be formed by lava flows originating from a volcanic hot spot. Lava from this type of volcano is high in basalt content, which affects both its flow properties and the formations it creates. Geologists have actually…
Galapagos Week: Pistol Shrimp
One of the most striking things about snorkeling in the Galapagos was how loud it was underwater. There were hardly any boats nearby, but every time my ears dipped below the surface, I could hear a constant cacophony of sound. Some it came from waves against the sand, some of it was the sound of…
Galapagos Week: Marine Iguanas
One of the most unique inhabitants of the Galapagos Islands is the marine iguana. These reptiles live in colonies of thousands and subsist entirely on marine algae. Smaller iguanas are intertidal feeders, grazing on green and red algae when it is exposed near low tide. But the largest iguanas feed near midday by swimming out…
Galapagos Week: Introduction
One hundred and eighty-two years ago today, the H.M.S. Beagle reached the Galapagos archipelago carrying, among others, naturalist Charles Darwin. The ship would spend the next month exploring the islands, and Darwin’s experiences during that time, and the specimens he collected, would ultimately lead him to propose the concept of evolution. I had the incredible opportunity…
Farewell, Cassini!
Tomorrow one of the most prolific and beloved spacecraft missions will come to an end when the Cassini spacecraft makes its final plunge into Saturn. After nearly 20 years in space and 13 years orbiting Saturn, the Cassini mission is close to running out of fuel. To prevent the craft from contaminating one of Saturn’s…
Lift Over Wings
One of the most vexing topics for fluid dynamicists and their audiences is the subject of how wings generate lift. As discussed in the video above, there are a number of common but flawed explanations for this. Perhaps the most common one argues that the shape of the wing requires air moving over the top…