This paper presents a way of modelling turbulence in multiphase flows within the context of the Reynolds-Stress Model. The model has been implemented in the general-purpose unstructured finite volume code Fluent V6. Two multiphase turbulence approaches were considered: mixture and dispersed models. The mixture model solves the Reynolds-stress transport equations on the mixture level only. The d...

In this paper a hybrid modulation scheme based on pulse position modulation (PPM) and binary phase shift keying subcarrier intensity modulation (BPSK-SIM) schemes for free-space optical communications is proposed. The analytical bit error rate (BER) performance is investigated in weak and saturated turbulence channels and results are verified with the simulation data. Results show that performa...

A theory of the effect of the geodesic acoustic mode !GAM" on turbulence is presented. Two synergistic issues are elucidated: namely, the physics of the zonal flow modulation and its role in the L-H transition, and the role of the GAM wave group propagation in turbulence spreading. Using a wavekinetic modulational analysis, the response of the turbulence intensity field to the GAM is calculated...

Stochastic Coherent Adaptive Large-Eddy Simulation is a novel approach to the numerical simulation of turbulence, based upon the wavelet thresholding filter, where the coherent energetic eddies are solved while modelling the influence of the less energetic background flow. In this study, in order to examine the quality and reliability of the method, additional explicit wavelet filtering is intr...

The nature of nonlinear interactions in gyrokinetic turbulence, driven by the ion-temperature gradient instability, is investigated using direct numerical simulations in toroidal flux tube geometry. To account for the level of separation existing between scales involved in an energetic interaction, the degree of locality of the free energy scale flux is analyzed employing Kraichnan's infrared (...

A power system is a nonlinear one. When turbulence occurs in the power system, the stability of the system depends on the initial operating conditions and the nature of the turbulence. Nowadays renewable energy sources including photovoltaic have a key role to meet high demand of modern societies and to maintain voltage of the buses, while they also provide clean electrical energy. However, inc...

Turbulence calculations with a 3D collisional fluid plasma model demonstrate qualitative and semi-quantitative similarity to experimental data in the Large Plasma Device [W. Gekelman et al., Rev. Sci. Inst. 62, 2875 (1991)], in particular for the temporal spectra, fluctuations amplitude, spatial correlation length, and radial particle flux. Several experimentally observed features of plasma tur...

Transitions from turbulence to order are studied experimentally in thin fluid layers and in magnetically confined toroidal plasma. It is shown that turbulence self-organizes through the mechanism of spectral condensation in both systems. The spectral redistribution of the turbulent energy leads to the reduction in the turbulence level, generation of coherent flow, reduction in the particle diff...

In recent years, there has been a renewed interest in the impact of turbulence on aquatic organisms. In response to this interest, a novel instrument has been constructed, TURBOGEN, that generates turbulence in water volumes up to 13 l. TURBOGEN is fully computer controlled, thus, allowing for a high level of reproducibility and for variations of the intensity and characteristics of turbulence ...

Understanding turbulence in fusion plasmas has become a crucial task in order to achieve sufficient confinement level in large-scale devices like ITER. The ELMFIRE full f nonlinear gyrokinetic simulation code has been developed for calculation of plasma evolution and dynamics of turbulence in tokamak geometry. Code ELMFIRE is based on a particle-in-cell algorithm with direct implicit treatment ...