Team burst bubble on cyclone secrets

French researchers have discovered that vortices created in soap bubbles behave like hurricanes in the atmosphere.

The turbulent surface of a soap bubble can gives us clues as to the random fluctuations of hurricanes.

Soap bubbles have enabled the researchers to characterise for the first time the random factor that governs the movement and paths of vortices. The findings, the researchers hope, could lead to a better understanding of such increasingly common and often devastating atmospheric phenomena.

Hamid Kellay, a researcher at the Centre de Physique Moléculaire Optique et Hertzienne, said: “A soap bubble is an ideal model for studying the atmosphere because it has analogous physical properties and, like the atmosphere, it is composed of a very thin film in relation to its diameter.”

The researchers created a half soap bubble that they heated at the ‘equator’ and then cooled at the ‘poles’, thereby creating a single large vortex, similar to a hurricane, in the wall of the bubble. The researchers studied the movement of this vortex, which fluctuates in a random manner. This is characterised by a law known as a superdiffusive law, well known to physicists, but which had not until then been observed in the case of single vortices in a turbulent environment.

The disconcerting resemblance between vortices on soap bubbles and hurricanes led the researchers to study their similarities. By analysing in detail the trajectories of certain recent hurricanes, the researchers measured the random factor that is always present in the movement of hurricanes. They then demonstrated the remarkable similarity of these fluctuations with those that characterise the disordered movement of the vortices that they created on soap bubbles.

Taking this random factor into account in predicting the trajectory of hurricanes will be useful in anticipating the probability of impact on a given site. Although the mean trajectory of hurricanes (without any fluctuations) is beginning to be well simulated by meteorologists, this random factor has, until now, been poorly understood.

This discovery highlights a universality in the statistics of trajectory fluctuations and should make it possible in the future to better predict the behavior of hurricanes and anticipate the risks.

The results are published in the journal Physical Review Letters.