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Abstract

We study the properties of various Eulerian contributions to fluid particle acceleration
by using well-resolved direct numerical simulations of isotropic turbulence, with the
Taylor-scale Reynolds number Rλ in the range 140–1300. The variance of convective
acceleration, when normalized by Kolmogorov scales, increases as Rλ, consistent with
simple theoretical arguments, but differing from classical Kolmogorov’s phenomenology,
as well as Lagrangian extension of Eulerian multifractal models. The scaling of the local
acceleration is also linear in Rλ to the leading order, but more complex in detail. The
strong cancellation between the local and convective acceleration—faithful to the random
sweeping hypothesis—results in the variance of the Lagrangian acceleration increasing
only as R0.25λ , as recently shown by Buaria and Sreenivasan [Phys. Rev. Lett. 128, 234502
(2022)]. The acceleration variance is dominated by the irrotational pressure gradient
contribution, whose variance essentially follows the R0.25
λ scaling; the solenoidal viscous
contributions are comparatively small and follow R0.13
λ , which is the only acceleration
component consistent with multifractal prediction.