the design and optimization of hydrocyclones using cfd techniques are gaining popularity and the key to a successful simulation lies with the accurate description of the high turbulent swirling behavior of the flow. this paper presents a detailed comparison between the omega rsm and the rng k–e turbulence model, which are both derived specially for modeling swirling or rotational flow, in the s...

The airflow in the modeled glottal constriction was simulated by the solutions of the Navier-Stokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow in generalized, nonorthogonal coordinates using a numerical method. A two-dimensional model of laryngeal flow is considered and aerodynamic properties are calculated for both laminar and turbulent steady flows...

We determine the nonlinear drift velocities of the mean magnetic field and nonlinear turbulent magnetic diffusion in a turbulent convection. We show that the nonlinear drift velocities are caused by the three kinds of the inhomogeneities, i.e., inhomogeneous turbulence; the nonuniform fluid density and the nonuniform turbulent heat flux. The inhomogeneous turbulence results in the well-known tu...

one of the popular and well known models in boundary layer that is implemented in most of the operational and familiar models is the mellor-yamada model of atmospheric boundary layer. one reason that this model is so popular is its ability in simulations and exposing of different phenomena in the boundary layer. this model has been constructed based on second order closure hypothesis. beside al...

Laser Doppler Velocimetry (LDV) has been employed to determine pseudo-turbulence characteristics of the flow field around bubble train forming in non-Newtonian caboxymethylcellulose (CMC) aqueous solution at low gas flow rate condition. The Reynolds stress and turbulent intensity of the liquid were investigated by means of Reynolds time-averaged method. The experimental results show that ax...

In this paper, an enhancement design of communication system using optical radio frequency (RF) waves in free space optical communication (FSO) system is presented. To our knowledge, it is the first time that the effect of Gamma-Gamma turbulent channel model on the performance of the proposed system is analyzed and simulated. To obtain an optical communication system with good performance and h...

A detection method based on sensitization of a squared double differentiated signal is developed which discriminates the turbulent zones from laminar zones quite accurately. The procedure adopts a variable threshold and a variable hold time of the order of the Kolmogorov time scale. The output file so generated, includes all the information for further analysis of the turbulent signal.

In this paper the flow behaviour over a number of car bodies is studied. For this purpose the unsteady 2-D incompressible Navier-Stokes equations have been applied. After averaging and nondimensionalizing the equations, the system of equations has been transformed from the Cartesian (x-y) coordinates to a body fitted generalized (-) coordinate. As the flow is incompressible, the density in the ...

Transition phenomena between thermal noise state and turbulent state observed in a submarginal turbulent plasma are analyzed with statistical theory. Time-development of turbulent fluctuation is obtained by numerical simulations of Langevin equation which contains hysteresis characteristics. Transition rates between two states are analyzed. Transition from turbulent state to thermal noise state...

Turbulent wake is crucial for the visually appealing effects of liquid. Unfortunately, it is challenging to realistically simulate this phenomenon with ring-shaped vortical structures. To tackle this issue, we propose a filament-based turbulent wake synthesis method for realistically simulating the turbulent wake with ring-shaped vortical structures. The filaments are sampled at the separation ...