The modification of turbulence in the edge plasma of the DIII–D tokamak at the transition from the low to the high mode of confinement is investigated with a phase-contrast imaging diagnostic. The amplitude and radial correlation length of the turbulence in the confinement region decrease at the transition, whereas the decorrelation time increases. The transition w Ž . x model of Biglari, Diamo...

intake system design as well as inlet ports and valves configuration is of paramount importance in the optimal performance of internal combustion engines. in the present study, the effect of inlet ports design is investigated on om-457la diesel engine by using a cfd analysis and the avl-fire code as well. a thermodynamic model of the whole engine equipped with a turbocharger and an intercooler ...

In this study, modeling of a fuel jet which has been injected by high pressure into a low-pressure tank are investigated. Due to the initial conditions and the geometry of this case and similar cases (like CNG injectors in internal combustion engines (ICE)), the barrel shocks and Mach disk are observed. Hence a turbulence and transient flow will be expected with lots of shocks and waves. Accord...

A new code aimed at the solution of three-dimensional intemal laminar and turbulent compressible flows is presented. The solution procedure is based on the scalar form of the approximate factorization method. The Navier-Stokes equations in mass-averaged form are iterated in time until a steady solution is reached. Evidence is given to the implicit treatment of diffusive terms that proved able t...

Atmospheric turbulence causes most weather-related aircraft incidents. Commercial aircraft encounter moderate-or-greater turbulence tens of thousands of times each year worldwide, injuring probably hundreds of passengers (occasionally fatally), costing airlines tens of millions of dollars and causing structural damage to planes. Clear-air turbulence is especially difficult to avoid, because it ...

We derive expressions for the spectral emissivity and absorptivity of acoustic radiation by low Mach number (M ~ 1) turbulent fluids. The emissivity and absorptivity depend on the manner in which the turbulence is excited. We consider three types of turbulence. The first is free turbulence, that is, turbulence which is not subject to external forces. The second and third examples are special ca...

In the following paper, the effects of a choked jet exhausted from the base of a non-lifting body on its total and base drags at sub-sonic and transonic regimes has been numerically investigated. Having surveyed the results of some turbulence models and after comparing with experimental results, an appropriate turbulence model i.e. SST K-?, has been chosen and this model has been used in the su...

In this work, the time-dependent solution for Lotka-Volterra Predator-Prey model is derived with help of Lambert W function. This allows an exact analytical expression period associated limit-cycle oscillations (LCO), and also response time between predator prey population. These results are applied to predator-prey interaction zonal density corrugations turbulent particle flux in gyrokinetic s...

The nonlinear mean-field dynamo due to a shear-current effect in a nonhelical homogeneous turbulence with a mean velocity shear is discussed. The transport of magnetic helicity as a dynamical nonlinearity is taken into account. The shear-current effect is associated with the W×J term in the mean electromotive force, where W is the mean vorticity due to the large-scale shear motions and J is the...

Characteristics of rotor blade tip clearance flow in axial compressors can significantly affect their performance and stable operation. It may also increase blade vibrations and cause detrimental noises. Therefore, this paper is contributed to investigate tip leakage flow in a low speed isolated axial compressor rotor blades row. Simulations are carried out on near-stall condition, which is val...