In order to study the characteristics of turbulent diffusion over an urban area, constant-volume balloons with transponders were released at altitudes of 200 and 400 m, and their behavior was observed over the Tokyo Metropolitan area. The atmospheric diffusivities are derived from the Lagrangian properties of the balloons, in relation to the temperature lapse rate and the turbulent intensity. T...

An oscillating grids turbulence generator was constructed for studies of two new effects associated with turbulent transport of particles, turbulent thermal diffusion and clustering instability. These effects result in formation of large-scale and small-scale inhomogeneities in the spatial distribution of particles. The advantage of this experimental set-up is the feasibility to study turbulent...

Lagrangian statistics from millions of particles are used to study the turbulent entrainment mechanism in a direct numerical simulation of a turbulent plane jet at Re(λ) ≈ 110. The particles (tracers) are initially seeded at the irrotational region of the jet near the turbulent shear layer and are followed as they are drawn into the turbulent region across the turbulent-nonturbulent interface (...

The paper suggests a stationary model of the vertical distribution of the concentration of suspended sediment in the bottom layer of a natural water body with a flat bottom. The model explains the concentration distribution, formed jointly by the settling of suspended particles and turbulent diffusion. The flow is assumed geostrophic above the bottom-influenced layer, while in the bottom layer ...

Fast particles diffusing along magnetic field lines in a turbulent plasma can diffuse through and then return to the same eddy many times before the eddy is randomized in the turbulent flow. This leads to an enhancement of particle acceleration by largescale compressible turbulence relative to previous estimates in which isotropic particle diffusion is assumed.

Physical similarity and mathematical equivalence of continuous diffusion and particle random walk form one of the cornerstones of modern physics and the theory of stochastic processes. In many applied models used in simulation of turbulent transport and turbulent combustion, mixing between particles is used to reflect the influence of the continuous diffusion terms in the transport equations. W...

Turbulent wake is crucial for the visually appealing effects of liquid. Unfortunately, it is challenging to realistically simulate this phenomenon with ring-shaped vortical structures. To tackle this issue, we propose a filament-based turbulent wake synthesis method for realistically simulating the turbulent wake with ring-shaped vortical structures. The filaments are sampled at the separation ...

The origin and sustenance of large scale galactic magnetic fields has been a long standing and controversial astrophysical problem. Here an alternative to the “standard” α−Ω mean field dynamo and primordial theories is pursued. The steady supply of supernovae induced turbulence exponentiates the total field energy, providing a significant seed mean field that can be linearly stretched by shear....