Non-Gaussianity in turbulent relative dispersion. (25th May 2019)

• Record Type: Journal Article
• Authors: Devenish, B. J.; Thomson, D. J.
• Is Part Of: Journal of fluid mechanics. Volume 867(2019)
• Page Start: 877
• Page End: 905
• Publication Date: 2019-05-25
• Subjects: isotropic turbulence, -- turbulence modelling, -- turbulence theory; Fluid mechanics -- Periodicals; 532.005
• DOI: 10.1017/jfm.2019.114
• Languages: English
• ISSNs: 0022-1120

Abstract

Abstract : We present an extension of Thomson's ( J. Fluid Mech., vol. 210, 1990, pp. 113–153) two-particle Lagrangian stochastic model that is constructed to be consistent with the $4/5$ law of turbulence. The rate of separation in the new model is reduced relative to the original model with zero skewness in the Eulerian longitudinal relative velocity distribution and is close to recent measurements from direct numerical simulations of homogeneous isotropic turbulence. The rate of separation in the equivalent backwards dispersion model is approximately a factor of 2.9 larger than the forwards dispersion model, a result that is consistent with previous work.