A Langevin Equation for the Turbulent Vorticity
The vorticity field of fully developed turbulence displays a complex spatial structure consisting of a large number of entangled filamentary vortices (see illustration). As a consequence, the PDF of the vorticity shows a highly non-Gaussian shape with pronounced tails. In the present work a kinetic theory for the turbulent vorticity is presented. Under certain conditions the arising equation may be interpreted as a Fokker- Planck equation giving rise to a Langevin model. The appearing unknown conditional averages are estimated from direct numerical simulations. The Langevin model is shown to reproduce the single point vorticity PDF.
KeywordsDirect Numerical Simulation Langevin Equation Multiplicative Noise High Order Statistic Conditional Average
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