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Updated: Jul 6, 2026
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Sufficient condition for Gaussian departure in turbulence
Daniela Tordella1, Michele Iovieno, Peter Roger Bailey
1Dipartimento di Ingegneria Aeronautica e Spaziale, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. daniela.tordella@polito.it
Summary
Mixing two turbulent fields with different kinetic energies creates an inhomogeneous field. This study shows a turbulent energy gradient is sufficient for intermittency and Gaussian departure in turbulence.
Area of Science:
- Fluid Dynamics
- Turbulence Research
- Computational Physics
Background:
- Turbulent fields with differing kinetic energies are fundamental to understanding complex fluid behaviors.
- Investigating the simplest inhomogeneous turbulent fields provides insights into fundamental turbulence dynamics.
Purpose of the Study:
- To numerically simulate the interaction of two decaying isotropic turbulent fields with varying kinetic energies.
- To analyze the resulting shearless mixing, anisotropy, intermittency, and energy transport dynamics.
Main Methods:
- Numerical experiment simulating two time-decaying isotropic turbulent fields.
- Initial kinetic energy matching over a narrow region with hyperbolic tangent variation.
- Analysis of temporal evolution, asymptotic behavior, and energy ratios (E1/E2).
Main Results:
- Observed anisotropy and intermittency in velocity and velocity derivative statistics.
- Demonstrated that a turbulent energy gradient is sufficient for intermittency.
- Found pressure transport to be significant during mixing, comparable to turbulent velocity transport.
Conclusions:
- The presence of a turbulent energy gradient is the minimal requirement for Gaussian departure in turbulence.
- Turbulent penetration reaches 1.2 times the nominal mixing layer width under specific high-energy ratio conditions.
- Findings suggest a new hypothesis linking turbulent energy gradients to non-Gaussian turbulence characteristics.
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