– Spiral wave and turbulence control in excitable media by applying periodic pacing on system’s boundary is investigated. It is found that spiral waves can be always successfully controlled by boundary periodic forcing with suitable forcing amplitude and frequency. Turbulence caused by spiral-wave breakup is uncontrollable by the boundary pacing, whatever the forcing amplitude and frequency, if...

The mechanics of inhomogeneous turbulence in and adjacent to interfacial layers bounding turbulent and non-turbulent regions are analysed. Different mechanisms are identified according to the straining by the turbulent eddies in relation to the strength of the mean shear adjacent to, or across, the interfacial layer. How the turbulence is initiated and the topology of the region of turbulence a...

Comparative studies between a toroidal low-temperature plasma and drift-Alfvén-wave simulations were carried out in order to investigate the microscopic structure of turbulence. The dimensionless plasma parameters in the TJ-K torsatron [Krause 2002] are similar to those in the edge of a fusion plasma. At the same time the fluctuations can be fully diagnosed by probe arrays. Fluctuation spectra ...

Gas holdup and bubble size are important parameters for simulation and designing in bubble column reactors. Because based on these parameters, the available gas-liquid interfacial area is defined for mass transfer. In this paper, the results of applying magnetic fields on the velocity field and volume fraction of gas holdup are reported. Hydrodynamics of the bubble column in the reactors is inv...

The optimal placement of sensors for the estimation of turbulence model parameters in computational fluid dynamics is presented. The information entropy (IE), applied on the posterior uncertainty of the model parameters inferred from Bayesian analysis, is used as a scalar measure of uncertainty. Using an asymptotic approximation, the IE depends on nominal values of the CFD model and prediction ...

BACKGROUND This study is aimed to evaluate the clinical significance of heart rate turbulence (HRT) parameters in predicting the prognosis in patients with chronic heart failure (CHF). METHODS From June 2011 to December 2012, a total of 104 CHF patients and 30 healthy controls were enrolled in this study. We obtained a 24-hour Holter ECG recording to assess the HRT parameters, included turbul...

in this paper the heating process in a box annealing unit is simulated and the effect of various parameters involved in the process is examined. for this purpose, the full naiver-stokes equations along with the standard k- turbulence model are solved in the fluid region using the finite volume approach. in the solid area the conduction heat transfer equation is employed using approporate surfac...

This study is to explore the numerical features of a particle-mesh algorithm developed for a stand-alone joint velocity-frequency-composition PDF method for turbulent reactive flows. Numerical experiments are performed on a piloted-jet nonpremixed turbulent flame of methane to characterize and quantify various numerical errors in terms of numerical parameters: number of particles per cell Npc, ...

Obese subjects are more prone to sudden deaths and arrhythmias than non-obese subjects. Heart rate turbulence (HRT) impairment reflects cardiac autonomic dysfunction, in particular impaired baroreflex sensitivity and reduced parasympathetic activity. Our aim was to evaluate the cardiac autonomic function in obesity by the HRT method. Ninety obese subjects and 112 healthy subjects were included ...

Monin-Obukhov theory predicts the well-known log-linear form of the vertical wind speed profile. A turbulence intensity profile can be estimated from this by assuming that the standard deviation of the wind speed is proportional to the friction velocity. Two parameters, namely the aerodynamic surface roughness length and the MoninObukhov length, are than needed to predict the vertical wind spee...