Implications of local decorrelator growth-rate statistics for Lagrangian chaos

Investigate the implications of the observed distributions of the local growth-rate fields \(\lambda_S(\mathbf{x})\) and \(\lambda_\eta(\mathbf{x})\)—including exponential and power-law tails—for Lagrangian chaos in three-dimensional, forced, homogeneous and isotropic Navier–Stokes turbulence.

Background

By measuring spatially local exponents for decorrelator growth, the authors find exponential tails for the strain contribution $\lambda_S(\mathbf{x})$ and power-law tails for the viscous contribution $\lambda_\eta(\mathbf{x})$. These findings point to strong intermittent fluctuations that could affect Lagrangian properties of turbulence, such as particle or tracer separation statistics and Lyapunov exponents.

The paper does not analyze these Lagrangian implications and explicitly defers them, identifying this as a direction for future investigation tied to the detailed statistics of $\beta_S$ and $\beta_\eta$.