Spatiotemporal turbulence or defect-mediated turbulence exists quite generally in excitable and oscillatory media such as chemical turbulence in reaction-diffusion systems and electrical turbulence in cardiac muscle. In many situations spatiotemporal turbulence is very undesirable. For example, ventricular fibrillation, the major reason behind sudden cardiac death, is a turbulent cardiac electr...

We present the results of a derivation of the fluctuation energy transport matrix for the two-field Hasegawa-Wakatani model of drift wave turbulence. The energy transport matrix is derived from a two-scale direct interaction approximation assuming weak turbulence. We examine different classes of triad interactions and show that radially extended eddies, as occurs in penetrative convection, are ...

Anomalous transport of heat and particles is known to be a key issue for fusion devices. In the present paper the anomalous transport of fast ions is investigated. High transit frequencies of the fast ions lead to the assumption that there is only very weak interaction with the low-frequency turbulence. However, our results indicate a significant fast ion particle transport due to the turbulenc...

CFD (Computational Fluid Dynamics) simulation is the main research method for assessing the wind environment around building complexes. Recent research showed the importance of turbulence models used in simulation and different turbulence models were developed to improve the precision of CFD simulation results. In this paper, a comparison of different turbulence models in simulating wind enviro...

Goldreich-Sridhar model of incompressible turbulence provides an elegant approach to describing strong MHD turbulence. It relies on the fact that interacting Alfvénic waves are independent and have random polarization. However, in case of strong interaction a spontaneous local assymetry can arise. We used direct numerical simulations to show that polarization alignment occurs and it grows large...

Simulation of turbulence boiling, generation of vapour and predication of its behaviour are still subject to debate in the two-phase flow area and they receive a high level of worldwide attention. In this study, a new arrangement of the three dimensional governing equations for turbulence two-phase flow with heat and mass transfer are derived by using ensemble averaging two-fluid model and ...

Turbulence analysis of flow inside a hydrocyclone is carried out using commercially available CFD software ANSYS-CFX (release 11.0). Commercial CFD software(s) and their turbulence models have come a long way in accurately predicting the flow inside a hydrocyclone, both at the mean as well as at the turbulence level. Previous studies have shown, the more accurate the turbulence prediction is, t...

The main objective of the work presented in this paper will be to present and discuss the development and implementation of a numerical model to simulate soot formation and depletion in turbulent diffusion flames. The relevance of such model lays on the importance of tying the formation of soot to the ongoing reaction mechanism so that it is fully integrated into the combustion process. The mod...

We study the propagation of localised disturbances in a turbulent, but momentarily quiescent and unforced shell model (an approximation of the Navier-Stokes equations on a set of exponentially spaced momentum shells). These disturbances represent bursts of turbulence travelling down the inertial range, which is thought to be responsible for the intermittency observed in turbulence. Starting fro...

We present a study of the multiscaling of time-dependent velocity and magnetic-field structure functions in homogeneous, isotropic magnetohydrodynamic (MHD) turbulence in three dimensions. We generalize the formalism that has been developed for analogous studies of time-dependent structure functions in fluid turbulence to MHD. By carrying out detailed numerical studies of such time-dependent st...