Theoretical approaches to low-frequencymagnetized turbulence in collisionless and weakly collisional astrophysical plasmas are reviewed. The proper starting point for an analytical description of these plasmas is kinetic theory, not fluid equations. The anisotropy of the turbulence is used to systematically derive a series of reduced analytical models. Above the ion gyroscale, it is shown rigou...

[1] The paper investigates the influence of relative bend curvature on secondary flow, energy losses, and turbulence in sharp open-channel bends. These processes are important in natural streams with respect to sediment transport, the bathymetry and planimetry, mixing and spreading of pollutants, heat, oxygen, nutrients and biological species, and the conveyance capacity. Laboratory experiments...

We study the statistics of density for supersonic turbulence in a medium with magnetic pressure larger than the gaseous pressure. This study is motivated by molecular cloud research. Our simulations exhibit clumpy density structures, which contrast increases with the Mach number. At 10 Machs densities of some clumps are three orders of magnitude higher than the mean density. These clumps give r...

Two combustion models for turbulent premixed combustion in the flamelet regime are developed for unsteady simulations. The first model is a convensional G equation flamelet model and the main issues discussed are the subgrid closure. The second model is based on the Linear-Eddy Model. Both models are used in simulation of turbulent stagnation point flames. The heat release and turbulence intens...

This article reviews recent work in the area of advanced turbulence modeling for complex three-dimensional flows of engineering interest. The term “advanced” refers herein to models that resolve the near-wall flow and account for the anisotropy of the Reynolds stresses. Representative such models, including full Reynolds-stress transport and non-linear, two-equation models, that have already be...

We compute 3D models of supersonic, sub-Alfv enic, and super-Alfv enic decaying turbulence, with initial rms Alfv en and Mach numbers ranging up to ve, and an isothermal equation of state appropriate for star-forming interstellar clouds of molecular gas. We nd that in 3D the kinetic energy decays as t ? , with 0:85 < < 1:2. In 1D magnetized turbulence actually decays faster than unmagnetized tu...

We review the Parisi-Frisch [1] MultiFractal formalism for Navier– Stokes turbulence with particular emphasis on the issue of statistical fluctuations of the dissipative scale. We do it for both Eulerian and Lagrangian Turbulence. We also show new results concerning the application of the formalism to the case of Shell Models for turbulence. The latter case will allow us to discuss the issue of...

We are focused on understanding small-scale processes that influence the ocean’s thermodynamic and dynamic properties on the sub-mesoscale (scales less than 10 km). This includes the role of turbulence in modifying the upper ocean temperature and density structure. In the South China Sea, largeamplitude, nonlinear waves force turbulence in the seasonally variable continental shelf region. New o...

This review summarizes the argument for molecular clouds being dominated by turbulence, most likely super-Alfvénic turbulence. Five lines of observational evidence are given: molecular linewidths and line shapes, nonequilibrium chemical abundances, fractal cloud shapes, measurements of the dispersion of dust extinction through clouds, and Zeeman measurements of the field strength. Recent models...

Flow over a downstream-facing step is predicted using the F.E.M. A two-equation model of turbulence is employed where the transport of turbulence kinetic energy and dissipation rate are depicted using transport-type equations, i.e. the two-equation model of turbulence. The results obtained are compared with other models and experimental results. Generally, the model was found to be under-predic...