Helicity and geometric nature of particle trajectories in homogeneous isotropic turbulence

The role of helicity in Lagrangian turbulence is investigated using direct numerical simulation of homogeneous isotropic turbulence. Probability density functions and autocorrelations along a fluid particle trajectory associated with geometric quantities such as curvature and torsion of the Lagrangian trajectory are provided. The relationship between helicity and the ratio of torsion to curvature is investigated. We found that probability density functions of torsion and torsion normalized by curvature clearly show well-established slope in log–log plots. Finally, the relationship between helicity, acceleration and geometric quantities are discussed.