Langevin equation of a fluid particle in wall-induced turbulence

We derive the Langevin equation describing the stochastic process of fluid particle motion in wall-inducedturbulence (turbulent flow in pipes, channels, and boundary layers including the atmospheric surface layer).The analysis is based on the asymptotic behavior at a large Reynolds number. We use the LagrangianKolmogorov theory, recently derived asymptotic expressions for the spatial distribution of turbulent energydissipation, and also newly derived reciprocity relations analogous to the Onsager relations supplementedwith recent measurement results. The long-time limit of the derived Langevin equation yields the diffusionequation for admixture dispersion in wall-induced turbulence. for the Russian version, see Teoreticheskaya i Matematicheskaya Fizika, Vol. 163, No. 2, pp. 328–352, May, 201