Fossil turbulence and fossil turbulence waves can be dangerous

TL;DR

This paper discusses the concept of fossil turbulence, its properties, and its potential dangers, emphasizing that fossil turbulence patterns can carry energy and information from past turbulence events, which is often overlooked.

Contribution

It introduces a clear definition of fossil turbulence and fossil turbulence waves, highlighting their significance in understanding fluid dynamics and safety risks.

Findings

Fossil turbulence persists after turbulence ceases.

Fossil turbulence can carry energy and information.

Ignorance of fossil turbulence can lead to dangerous misinterpretations.

Abstract

Turbulence is defined as an eddy-like state of fluid motion where the inertial-vortex forces of the eddies are larger than any other forces that tend to damp the eddies out. By this definition, turbulence always cascades from small scales where vorticity is created to larger scales where turbulence fossilizes. Fossil turbulence is any perturbation in a hydrophysical field produced by turbulence that persists after the fluid is no longer turbulent at the scale of the perturbation. Fossil turbulence patterns and fossil turbulence waves preserve and propagate energy and information about previous turbulence. Ignorance of fossil turbulence properties can be dangerous. Examples include the Osama bin Laden helicopter crash and the Air France 447 Airbus crash, both unfairly blamed on the pilots. Observations support the proposed definitions, and suggest even direct numerical simulations of turbulence require caution.