In this validation work two turbulence models (k-ε and SST model) and two grids (a finer hybrid grid and a tetrahedral coarser grid) are considered in order to model helium release and dispersion. Simulation results are compared against an experiment of jet release phenomena in the Battelle Model Containment facility (BMC), a multi-compartment facility with a total volume of about 560 m. In the...

Numerical study of two dimensional supersonic hydrogen-air mixing layer is performed to investigate the effect of turbulence and chemical additive on ignition distance. Chemical reaction is treated using detail kinetics. Advection upstream splitting method is used to calculate the fluxes and one equation turbulence model is chosen here to simulate the considered problem. Hydrogen peroxide is us...

Optical turbulence, which develops in the transverse directions when a laser beam propagates through a medium, is considered in the framework of the two-dimensional Schrodinger equation with a weak cubic nonlinearity. This classical model of optical turbulence was studied by many authors, but stationary (Kolmogorov) spectra that transfer transverse energy of the waves from large spatial scales...

We study the statistics of single-particle Lagrangian velocity in a shell model of turbulence. We show that the small-scale velocity fluctuations are intermittent, with scaling exponents connected to the Eulerian structure function scaling exponents. The observed reduced scaling range is interpreted as a manifestation of the intermediate dissipative range, as it disappears in a Gaussian model o...

In this paper the impact of atmospheric turbulence on helicopter handling qualities is investigated using a simple random turbulence representation and a structural human pilot model. Linear approximation of the turbulence field and the frozen field concept are assumed. Effects of uniform field component and spatial gradients in the horizontal plane are individually evaluated on each axis. Turb...

In this work, statistical properties of compressible hydrodynamic and magnetohydrodynamic turbulence are studied using direct numerical simulations. The properties of turbulent flows change when average flow velocities within the turbulence exceed the speed of sound in the medium. High flow velocities lead to the formation of shocks, and some of the base assumptions of turbulence theories of in...

We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We find that the time scale for the energy cascade is consistent with the Goldreich-Sridhar model of strong MHD turbulence. Using higher order longitudinal structure functions we show that the turbulent motions in the plane ...

The spherical torus edge region is among the most challenging regimes for plasma turbulence simulations. Here, we measure the spatial and temporal properties of ion-scale turbulence in the steep gradient region of H-mode pedestals during edge localized mode-free, MHD quiescent periods in the National Spherical Torus Experiment. Poloidal correlation lengths are about 10 qi, and decorrelation tim...

A generalized exponential spectrum model is derived, which considers finite turbulence inner and outer scales and has a general spectral power law value between the range 3 to 5 instead of standard power law value 11/3. Based on this generalized spectrum model, a new generalized long exposure turbulence modulation transfer function (MTF) is obtained for optical plane and spherical wave propagat...