Spray tuning
If you’ve ever splattered paint on a canvas or sprayed a cookie sheet with oil, you likely created — aside from a minor mess — a shower of droplets, ranging from dime-sized splotches to pencil-point specks. Such droplet sizes may seem random, but now engineers at MIT can predict a liquid’s droplet size distribution, including the likelihood of producing very big and very small droplets, based on one main property: the liquid’s viscoelasticity, or stickiness. What’s more, the team has found that, past a certain stickiness, fluids will always exhibit the same relative range of droplet sizes. Knowing how big or small a liquid spray’s droplets may be can help researchers identify optimal fluids for a number of industrial applications, from preventing defects in automotive paint jobs, to fertilizing farm fields via aerial spraying. The researchers’ results were published in October in the journal Physical Review Letters. The paper’s lead author is Bavand...