The Old Road to Turbulence

Discovery Year Portrait Key Contribution
1500s Leonardo da Vinci Leonardo da Vinci: Documented early observations of turbulent flow.
1820s Claude-Louis Navier George Gabriel Stokes Claude-Louis Navier and George Gabriel Stokes: Formulated the foundational NS equations.
1883 Osborne Reynolds Osborne Reynolds: Characterized the transition to turbulence.
1941 Andrey Kolmogorov Andrey Kolmogorov: Proposed scaling laws of turbulence (K41).
1944 Werner Heisenberg Werner Heisenberg: Theoretical contributions to stability and dissipation models.
1946 Lars Onsager Lars Onsager: Introduced insights into fractal velocity fields and vortex structures.
1948-1952 Eberhard Hopf Eberhard Hopf: The functional equation for statistics of turbulence.
1956 Lev Landau Lev Landau: Advanced the understanding of hydrodynamic stability.
1985 Giorgio Parisi Uriel Frisch Giorgio Parisi and Uriel Frisch: Proposed multifractal models for turbulence.
2000-2022 K.R. Sreenivasan K.R. Sreenivasan: DNS studies uncovering scaling law violations.

Scaling Law Violations: The Dead End of the Old Road

Graph showing DNS scaling mismatch

Key Findings:

  • Kolmogorov's K41 model theory: Predicted universal scaling laws for velocity difference moments, including an index of \( \frac{2}{3} \) for the second moment.
  • This figure shows the effective index = logarithmic derivative of the second moment \( \langle \Delta v^2(r,t) \rangle \) plotted against \( \log \left( \frac{r}{\sqrt{t}} \right) \).
  • DNS simulations (\( 4096^3 \) lattice) using a novel method to extract effective indices from observed energy spectra contradicted any scaling law (a horizontal line on this plot).
Road Closed Detour