A theory of turbulence mechanics based on material failure

TL;DR

This paper introduces a novel theory that explains the transition to turbulence as a failure of fluid material, where viscous forces can no longer contain kinetic energy, leading to turbulence.

Contribution

The work proposes a new material failure-based model for turbulence transition, providing a predictive equation and matching experimental flow profiles.

Findings

Predicted flow profiles align with experimental data.

A new equation accurately predicts turbulence onset.

The theory offers a physical explanation based on material failure concepts.

Abstract

Considerable effort has been expended over the last 2 centuries into explaining the behavior of fluid flow after the onset of turbulence. While perturbations in the velocity field have been shown to explain turbulent transitions, a physical explanation of why flows become turbulent, based on the forces felt by the fluid particles, has remained elusive. In this work a new theory is proposed that attempts to explain the transition of fluid flow from laminar to turbulent as explained by the fluid material undergoing failure. In a vaguely similar sense to how fractures can occur in solids once the balance of momentum exceeds the capacity of the material, so too in a fluid, after sufficient kinetic energy has been achieved by a fluid packet, the viscous forces are unable to maintain the laminar behavior and the fluid packets receive a boost as the stored energy in the viscous bonds are transferred to the kinetic energy of the fluid. This new model is described in terms of fluid packets and the forces on a mass element and commonly-known turbulent flows are used as examples to test the theory. Predicted flow profiles from the theory match the experimental observations of averaged flow profiles and a new equation to predict the onset of turbulence for any flow is presented. This process of the fluid undergoing failure can be seen as a natural continuation of the prevailing wisdom of turbulence when viewed from a different frame of reference.