Meet a lot in nature, but the truth about them is a big unknown that makes even geniuses have a “headache”.
In the 15th century, Leonardo da Vinci – the eminent genius of Italy – happened to see the image of ripples radiating into a circle when a drop of water touched the surface of the lake next to where he lived. This phenomenon is now known as hydraulic jumps .
With his sharp mind, he worked hard to find the answer to this very familiar phenomenon.
However, even at the time of his death, his answer was still very vague, saying that this phenomenon was simply due to … the inertia of the water.
Ripples spread out in a circle when the water drops hit the surface of the lake.
In 1914, physicist John William followed in the footsteps of the Italian genius to find the source of those strange “hydraulic jumps” . Finally, he concluded that there are three factors that cause this phenomenon, including: viscosity (viscosity), kinetic energy (kinetic energy) and potential energy (potential energy).
According to William, when an object falls and hits the surface of the water at a certain height, gravitational potential energy will be generated. Along with that, the viscosity of the water will combine to create a kinetic force, creating spreading “water waves” as shown in the following illustration.
The gravitational potential energy from the vertical water flow, combined with the viscosity in the water, will produce waves of curled “wavelengths” as shown. There are three types: 1, 2a and 2b.
And this is the “real” image.
So is this the most “standard” answer or not?
In a latest report from the University of Cambridge, physicist Rajesh Bhagat and colleagues have found that: Gravitational potential does not play a major role in the phenomenon of Hydraulic Jump.
Instead, surface tension and viscous friction of water are the two main factors of this natural phenomenon.
Surface tension (Fs) occurs when there is a tension perpendicular (Fw) to the fluid plane as shown in the figure.
According to Bharat, after doing a series of experiments based on the height of the falling object (z), he found that the gravity of the Earth does not generate a large enough potential energy to affect the Hydraulic Jump, like have been questioned before.
“We have found that surface tension and viscosity are enough to balance the momentum of the water, and the role of gravity is very modest.”
“Understanding the formation mechanism of Hydraulic Jumps will be the first step in applying them to practice, namely cleaning vehicles or industrial equipment without wasting too much water,” Bharat said. added.
Although there will be many difficulties ahead, but surely, the solution of Bharat and his colleagues has satisfied the question that science has long been left open.