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Universal statistical properties of inertial-particle trajectories in three-dimensional, homogeneous, isotropic, fluid turbulence
, A. Gupta, D. Mitra, P. Perlekar, R. Pandit
Published in TU Delft
2015
Abstract
We obtain new universal statistical properties of heavy-particle trajectories in three-dimensional, statistically steady, homogeneous, and isotropic turbulent flows by direct numerical simulations. We show that the probability distribution functions (PDFs) P(φ), of the angle φ between the Eulerian velocity u and the particle velocity v, at a point and time, scales as P(φ) ∼ φ−γ, with a new universal exponent γ ≃ 4. The PDFs of the trajectory curvature κ and modulus θ of the torsion ϑ scale, respectively, as P(κ) ∼ κ−hκ, as κ → ∞, and P(θ) ∼ θ−hθ, as θ → ∞, with exponents hκ ≃ 2.5 and hθ ≃ 3 that do not depend on the Stokes number St. We also show that γ, hκ and hθ can be obtained by using simple stochastic models. We show that the number NI(t,St) of points (up until time t), at which ϑ changes sign, is such that nI(St) ≡ limt→∞ NI(tSt) ∼ St−∆, with ∆ ≃ 0.4 a universal exponent. t © TU Delft.
About the journal
JournalProceedings - 15th European Turbulence Conference, ETC 2015
PublisherTU Delft