The statistical properties of the Lagrangian acceleration vector of passive tracers in statistically steady rotating turbulence is studied by particle tracking velocimetry. Direct effects of the background rotation are the suppression of high-acceleration events parallel to the (vertical) rotation axis, the enhancement of high-acceleration events for the horizontal acceleration, and the strong ...

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...

I These equations are implemented in GBS, a 3D, flux-driven, global turbulence code with circular geometry, and the system is closed by the Poisson’s equation ω = ∇⊥φ [Ricci et al., PPCF 2012] I System is completed with a set of first-principles boundary conditions applicable at the magnetic pre-sheath entrance where the magnetic field lines intersect the limiter [Loizu et al., PoP 2012]: v‖i =...

The study presents a computational analysis of vane pump using two different turbulence models namely κ-ε and κ-ω. geometry characteristics the were obtained by disassembly further measurements. CAD model for domain was developed in SOLIDWORKS®. CFD modeling powered ANSYS®, which allowed evaluation mesh types models. A total set six simulations performed to obtain comparison schemes evaluation....

A wall–distance–free version of the Spalart–Allmaras (SA) one–equation model is proposed to account for the distinct effects of low-Reynolds number (LRN) and wall proximity. The turbulent kinetic energy k and the dissipation rate ǫ are evaluated using the ν̃t–transport equation together with some empirical relations. The model coefficients/functions preserve the anisotropic characteristics of tu...

The purpose of this article is numerical verification of the theory of weak turbulence. We performed numerical simulation of an ensemble of nonlinearly interacting free gravity waves (swell) by two different methods: solution of primordial dynamical equations describing potential flow of the ideal fluid with a free surface and, solution of the kinetic Hasselmann equation, describing the wave en...

The Taylor-Reynolds and Reynolds number (Reλ and Re) dependence of the dimensionless energy dissipation rate cǫ = ǫL/u 3 1,rms is derived for statistically stationary isotropic turbulence, employing the results of a variable range mean field theory. Here, ǫ is the energy dissipation rate, L is the (fixed) outer length scale, and u1,rms a rms velocity component. Our fit-parameter free results fo...

Jet nozzle is a core component of the hydraulic perforating fracturing tool, and design structure directly affects effectiveness efficiency. In this paper, flow field characteristics nozzles are calculated by SST k- ω turbulence model. The results show that parameters significantly influence jet performance. Through orthogonal experiments, conical-cylindrical geometric preliminarily optimized a...

Developing boundary layer flow and the flow over a backward-facing step are studied here. The LRN PANS k − ε [1] and the WALE turbulence model [2] are used as SGS models. The PANS (Partially AveragedNavier-Stokes) modelling approach [3, 4] is a modified k − ε model that can operate in both RANS and LES mode. An extension of PANS based on a four-equation k− ε− ζ − f model was recently proposed [...