Session 1C: Inaugural Lectures by Fellows / Associates

Covid-19 and Flame blowout in jet engines: What is in common?

Abstract: Critical phenomena such as stock market crashes, earthquakes, Rayleigh-Taylor instabilities, or avalanches that occur in disparate complex systems, show generic features on approaching a critical point, regardless of the specific physical processes that govern the dynamics. COVID-19 transmission and flame blowout in combustors are two unrelated phenomena; however, we unravel striking similarities between the two. We identified the presence of a hyperexponential growth decorated with log-periodic oscillations preceding flame blowout and during the early phase of extreme COVID-19 waves. In both cases, hyperexponential growth is accompanied by unbounded growth and finite-time singularity. The observation of oscillations decorating the power-law growth, which are periodic in logarithmic scale, known as log-periodic oscillations, unravel the existence of discrete scale invariance. Furthermore, flame blowout in real-world systems, as well as COVID-19 waves, are undesirable. Contrary to commonly believed exponential growth, the faster than exponential growth phase is hazardous and would entail stricter regulations to minimize further spread. Characterizing these log-periodic oscillations enable better prediction of the finite-time singularity in both cases.