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Free keywords:
isotropic turbulence; turbulence simulation; turbulence theory
Abstract:
We investigate the single-point probability density function of the
velocity in three-dimensional stationary and decaying homogeneous
isotropic turbulence. To this end, we apply the statistical framework of
the Lundgren-Monin-Novikov hierarchy combined with conditional
averaging, identifying the quantities that determine the shape of the
probability density function. In this framework, the conditional
averages of the rate of energy dissipation, the velocity diffusion and
the pressure gradient with respect to velocity play a key role. Direct
numerical simulations of the Navier-Stokes equation are used to
complement the theoretical results and assess deviations from
Gaussianity.
