We have all tried, at least once in our lives, to make a stone skip in the water.
With friends, family, or even alone, we have done it and it is definitely one of those things in life that generate pleasure and fun for no apparent reason. There are those who even with a lot of practice achieve the desired bounce.
Now, a recent study managed to decipher the physics behind the bouncing of stones in the water and its findings could be used in aviation.
A team led by Jie Tang at Southwest Jiaotong University in China carried out an investigation in which they built mathematical models to understand the operation of skipping stones. For this they used two physical principles, the first, the Magnus effect is the phenomenon under which the trajectory of a rotating object is affected with regard to the fluid in which it moves. The second is the Gyro Effect under which an object has the ability or tendency to maintain a defined course from its axis of rotation.
The scientists conducted an experiment in which a spinning metal sheet was thrown into the water, and they were able to measure the variations in its trajectory, speed, and spin as the disk repeatedly hit the liquid.
The result of the tests showed them that depending on the speed and the launch angle, the disc (or the stone) would have to reach or exceed 4 times the acceleration of gravity and in this way, it could bounce repeatedly, less than that force would mean that the object could slide through the water for a few moments and then sink without reaching any bounce.
But the speed and number of spins that the object can make in a limited period are also essential to maintain its stability and its course.
“Our results provide a new perspective to advance future studies in aerospace and marine engineering,” said Kun Zhao, co-author of the study.
The researchers believe that their calculations could be applied to airplanes or spacecraft and improve their ability to land in water and we hope to see this technology developed soon.