Surely you have noticed, every time you go to the bathroom to wash your hands or teeth, in this daily event, but one that has puzzled engineers for centuries: why does the water spread when it reaches the sink before it comes out? down the drain? That is, what physical behavior explains this momentary eddy that the water forms before leaving our sink?
Well, today this phenomenon is called hydraulic leap and was first documented by the famous inventor and painter Leonardo Da Vinci in the 16th century. Since the 1820s, scientists have believed that hydraulic jumps occur in part as a result of gravitational attraction. But an article published in the Journal of Fluid Mechanics has disproved this theory, assumed for almost two centuries.
Researcher Rajesh Bhagat, first author of the paper, fired jets of water up and to the sides on flat surfaces, and witnessed exactly the same hydraulic jumps as when water flowed down. Bhagat deduced that they could all be affected by the same factors: surface tension and viscosity.
By altering these attributes of the water, he was able to accurately obtain the size of the hydraulic jumps, regardless of the direction the water was moving, thus debunking classical gravitational theory as the cause. This type of hydraulic jump is known as a circular hydraulic jump.
His experiments and theory show that the surface tension of the liquid is the key to the process, and not gravity. These parameters had never before been recognized as the causes of this physical phenomenon, despite the fact that the problem had already been discussed by Da Vinci and many others since.
In Bhagat’s words: “This work represents a remarkable achievement in our understanding of the dynamics of thin fluid layers.”
On the way to more efficient use of water
It is important to note that, although H2O is a molecule that behaves in an extraordinary way compared to other substances in the universe, in terms of parameters such as density, the hydraulic jump is a physical phenomenon that occurs in all classes of fluids.
In any case, the great implication that understanding this process can have does refer to water: engineers could work on methods to drastically reduce the industrial use of water , an increasingly scarce commodity on our planet.
But, in addition, Bhagat hopes that his research will also be used to find new ways to help us use less water, not only on an industrial level, but also at home.
Although hydraulic jumps are harmless in the sinks and sinks of our homes, they can cause violent waves, turbulence and eddies in deeper water.
