Fluid Dynamics - Blog Posts
One of the most beautiful chemical reactions is the Belousov–Zhabotinsky reaction, and it’s the subject of the latest video from Beauty of Science. (Image and video credit: Beauty of Science; via PetaPixel; submitted by clogwog)
It's 2am.
I have an assignment due in two hours ago on the Hagen-Poiseuille equation and what it explains and how you derive it etc and link it to Bernoulli's principal.
Whipee for physics.
Fuck my physics degree apparently (cos I'm definitely failing this year)
For pedestrians, windy conditions can be uncomfortable or even downright dangerous. And while you might expect the buildings of an urban environment to protect people from the wind, that’s not always the case. The image above shows a simulation of ground-level wind conditions in Venice on a breezy day. While many areas, shown in blue and green, have lower wind speeds, there are a few areas, shown in red, where wind speeds are well above the day’s average. This enhancement often occurs in areas where buildings constrict airflow and funnel it together. The buildings create a form of the Venturi effect, where narrowing passages cause local pressure to drop, driving an increase in wind speed. Architects and urban designers are increasingly turning to numerical simulations and CFD to study these effects in urban environments and to search for ways to mitigate problems and keep pedestrians safe. (Image credits: CFD analysis - SimScale; pedestrians - Saltysalt, skolnv)
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When I post Slow Mo Guys videos, it often comes with a warning not to try this at home. For their latest video, that deserves an extra-special mention: seriously, don’t try this. In this video, Dan and Gav explode lithium-ion batteries. In the process, they discover a safety feature - namely vents on one face of the battery. Because runaway thermal reactions (a.k.a. explosions) are a possibility with this type of battery system, consumer-grade batteries are designed to try and prevent extreme damage. One of these outwardly visible safety features are these four vents that release gas when when the battery is too hot. By venting the gas, manufacturers keep the battery from exploding and sending hot chemicals and shrapnel in all directions. Instead the venting gas turns the entire battery into a miniature rocket. (Video and image credit: The Slow Mo Guys)
The team behind Beauty of Science decided to explore the four seasons in this video combining macro footage of crystal growth, chemical reactions, and fluid dynamics. It’s always a fun game with videos like this to try and guess exactly what makes the mesmerizing patterns we see. Are those blue streaming waves in Spring caused by alcohol shifting the surface tension in a mixture? Are the dots of color welling up in Autumn a lighter fluid bursting up from underneath a denser one? As fun as the visuals are, though, what really made this video stand out for me was its excellent use of “The Blue Danube” to tie everything together. Check it out and don’t forget the audio! (Video credit: Beauty of Science; via Gizmodo)
Inside the Squirting Cucumber
Though only 5 cm long, the squirting cucumber can spray its seeds up to 10 meters away. The little fruit does so through a clever combination of preparation and ballistic maneuvers. (Research and image credit: F. Box et al.; via Gizmodo) Read the full article
26 Oct (Intro. Number Theory)
This is by far the worst class that I have taken. Consistently I have been with the lowest grade, and my overall understanding of this class is abysmal. Despite being in my professor’s office every day.
In any case I make a point to strive for perfection, and not understanding something haunts me to my core. In any case I am forever hopeful. Im happy to be back, and I have lots to share
🎧 Momma Told Me - Earthgang
Stay Up y’all
28 April (Diff Eq.)
The struggle has been very real over the course of the last week. I failed a test (it was in the teens), my mom is still in the hospital, and some days are definitely better than others, but I am holding on.
I can’t in good faith give up everything that I’ve worked so hard to build. I have also been procrastinating. The Howard deadline is 30 April, and tbh I haven’t put my all into it (despite really wanting to attend the school).
Small update, but that’s all for today.
Stay up✌🏿
🎧 Trappin in Japan 4 - Ryan Celsius
In a recent video, Practical Engineering tackles an important and often-overlooked challenge in civil engineering: dam failure. At its simplest, a levee or dam is a wall built to hold back water, and the higher that water is, the greater the pressure at its base. That pressure can drive water to seep between the grains of soil beneath the dam. As you can see in the demo below, seeping water can take a curving path through the soil beneath a dam in order to get to the other side. When too much water makes it into the soil, it pushes grains apart and makes them slip easily; this is known as liquefaction. As the name suggests, the sediment begins behaving like a fluid, quickly leading to a complete failure of the dam as its foundation flows away. With older infrastructure and increased flooding from extreme weather events, this is a serious problem facing many communities. (Video and image credit: Practical Engineering)
Popcorn’s explosive pop looks pretty cool in high-speed video, but just watching it with a regular camera doesn’t show everything that’s going on. If we take a look at it through schlieren optics, the kernel’s pop looks even more extraordinary:
The schlieren technique reveals density differences in the gases around the corn–effectively allowing us to see what is invisible to the naked eye. The popcorn kernel acts like a pressure vessel until the expansion of steam inside causes its shell to rupture. The first hints of escaping steam send droplets of oil shooting upward. The kernel may hop as steam pours out the rupture point, causing the turbulent billowing seen in the animation above. As the heat causes legs of starch to expand out of the kernel, they can push off the ground and propel the popcorn higher. As for the eponymous popping sound, that is the result of escaping water vapor, not the actual rupture or rebound of the kernel! See more of the invisible world surrounding a popping kernel in the video below. (Image credits: Warped Perception, source; Bell Labs Ireland, source; WP video via Gizmodo; BLI video submitted by Kevin)
Watching a snowflake grow seems almost magical–the six-sided shape, the symmetry, the way every arm of it grows simultaneously. But it’s science that guides the snowflake, not magic. Snowflakes are ice crystals; their six-sided shape comes from how water molecules fit together. The elaborate structures and branches in a snowflake are the result of the exact temperature and humidity conditions when that part of the snowflake formed. The crystals look symmetric and seem to grow identical arms simultaneously because the temperature and humidity conditions are the same around the tiny forming crystals. And the old adage that no two snowflakes are alike doesn’t hold either. If you can control the conditions well enough, you can grow identical-twin snowflakes! (Video credit: K. Libbrecht)
The brilliant colors of a soap film reveal the fluid’s thickness, thanks to a process known as thin film interference. The twisting flow of the film depends on many influences: gravity pulls down on the liquid and tends to make it drain away; evaporation steals fluid from the film; local air currents can push or pull the film; and the variation in the concentration of molecules – specifically the surfactants that stabilize the film – will change the local surface tension, causing flow via the Marangoni effect. Together these and other effects create the dancing turbulence captured above. (Video credit: A. Filipowicz)