Angular statistics of Lagrangian trajectories in turbulence

Wouter J.T. Bos (1) , Benjamin Kadoch (2) , Kai Schneider (3)

1 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique
2 IUSTI - Institut universitaire des systèmes thermiques industriels
3 M2P2 - Laboratoire de Mécanique, Modélisation et Procédés Propres

The angle between subsequent particle displacement increments is evaluated as a function of the timelag in isotropic turbulence. It is shown that the evolution of this angle contains two well-defined power-laws, reflecting the multi-scale dynamics of high-Reynolds number turbulence. The proba-bility density function of the directional change is shown to be self-similar and well approximated by an analytically derived model assuming Gaussianity and independence of the velocity and the Lagrangian acceleration.

Mots clés: Homogeneous Isotropic Turbulence; curvature

Domaines: Mécanique des fluides [physics.class-ph]

Wouter J.T. Bos, Benjamin Kadoch, Kai Schneider. Angular statistics of Lagrangian trajectories in turbulence. Physical Review Letters, 2015, 114, pp.214502. ⟨10.1103/PhysRevLett.114.214502⟩. ⟨hal-01085070⟩