Final Report Summary - NEWTURB (New eddy-simulation concepts and methodologies for frontier problems in Turbulence)
NewTURB is a laboratory in-silico aimed to disentangle and model turbulence by changing the nature of the non-linear terms of Navier-Stokes equations, aspects otherwise inaccessible by using conventional experimental and numerical methods.
We have used novel approaches based on (i) surgeries of quadratic interactions with different contents of the inviscid invariants, Helicity and Energy; (ii) changing the number of the degrees of freedom, via a projection on a fractal-Fourier space; (iii) changing the symmetries imposed by the forcing mechanisms and by the boundary conditions.
The final aim was to disentangle universal (isotropic) from non-universal (anisotropic) aspects of turbulence across all scales, in sheared or under rotation for both Eulerian and Lagrangian turbulent statistics.
We have finally clarified the role played by Helicity in the reversal of the energy flux and on the development of small-scales turbulent fluctuations in flows under rotation and in thick layers. We have quantified the importance of Fourier mode reduction for intermittency, for phase-correlations and analysed the impact on the small-scale modelling in Large Eddy Simulations. We have highlighted new statistical signatures of strong coherent vortical structures in rotating turbulence and measured -for the first time- the statistics of inertial particles in flows under rotation. We have developed a set of new optimised data analysis tools for anisotropic fluctuations and models for particles’ advection in turbulent and stochastic flows. There are no doubts that NewTURB’s legacy will last long, having opened new avenues on the way to analyse and model the multi-scale energy transfer in flows of theoretical and applied interest.
We have used novel approaches based on (i) surgeries of quadratic interactions with different contents of the inviscid invariants, Helicity and Energy; (ii) changing the number of the degrees of freedom, via a projection on a fractal-Fourier space; (iii) changing the symmetries imposed by the forcing mechanisms and by the boundary conditions.
The final aim was to disentangle universal (isotropic) from non-universal (anisotropic) aspects of turbulence across all scales, in sheared or under rotation for both Eulerian and Lagrangian turbulent statistics.
We have finally clarified the role played by Helicity in the reversal of the energy flux and on the development of small-scales turbulent fluctuations in flows under rotation and in thick layers. We have quantified the importance of Fourier mode reduction for intermittency, for phase-correlations and analysed the impact on the small-scale modelling in Large Eddy Simulations. We have highlighted new statistical signatures of strong coherent vortical structures in rotating turbulence and measured -for the first time- the statistics of inertial particles in flows under rotation. We have developed a set of new optimised data analysis tools for anisotropic fluctuations and models for particles’ advection in turbulent and stochastic flows. There are no doubts that NewTURB’s legacy will last long, having opened new avenues on the way to analyse and model the multi-scale energy transfer in flows of theoretical and applied interest.