14 DAY TRIAL // In a interesting new research, experts were able to establish that sphere of different temperatures travel though liquids at different speeds. Such a discovery could have tremendous implications for the way submarines are built, and for how they move through water.
Using high-speed cameras, investigators were able to determine that spheres which had been previously heated up tended to fall through liquid twice as fast as spheres made of the same material, but which were kept cold.
The research team was even able to propose an explanation for this effect. They say that the phenomenon is akin to what happens when water droplets are poured inside a hot frying pan. The small drops begin to literally skate across the heated surface, before vaporizing.
This is called the Leidenfrost effect, and it apparently also affects spheres moving through liquid. The way this works is rather simple – as the water droplet touches the frying pan, a thin layer of vapors forms underneath.
As such, the droplet is stopped from evaporating immediately. Rather, it begins to levitate across the surface, which is what allows it to move in all directions before finally succumbing to the heat.
In the new study, an international group of physicists was able to determine that a reversed Leidenfrost effect was taking place as the sphere were falling through liquid. The phenomenon cut the drag left behind by the sphere by as much as 85 percent.
This is what allowed for decreased friction and increased speed, the experts say. The team used steel spheres for this study, which were heated to temperatures reaching 482 degrees Fahrenheit. A low-boiling point liquid was used as the medium.
As soon as the heated steel was suspended magnetically in the liquid, it formed a 200-micrometer layer of vapor around it, says team leader Ivan Vakarelski, who is based at the King Abdullah University of Science and Technology, in Saudi Arabia.
When the steel lost its heat, and cooled to around 266 degrees Fahrenheit, the protective vapor bubble burst, causing the sphere to decrease its speed again. At this point, the team is unsure how the new study will translate into real-world applications.
However, they say that the findings could benefit underwater science and military operations. It's just a matter of finding technologies to heat the surface of a submarine to hundreds of degrees Fahrenheit, Wired reports.