Consider the dynamics of turbulent flow in rivers, estuaries and floods. Based on the widely used k-ǫ model for turbulence, we use the techniques of centre manifold theory to derive dynamical models for the evolution of the water depth and of vertically averaged flow velocity and turbulent parameters. This new model for the shallow water dynamics of turbulent flow: resolves the vertical structu...

Recent progress and remaining challenges related to the understanding and prediction of turbulent flow are described. This is done by explaining the need for the development and basic features of unified turbulence models which integrate, recover and extend well known existing computational methods for turbulent flow calculations. The availability of unified turbulence models enables a signific...

A new subgrid eddy-viscosity model is proposed in this paper. Full details of the derivation of the model are given with the assumption of homogeneous turbulence. The formulation of the model is based on the dynamic equation of the structure function of resolved scale turbulence. By means of the local volume average, the effect of the anisotropy is taken into account in the generalized Kolmogor...

in the present work a two dimensional numerical investigation of steam flows in a turbine blade passage is performed. a finite volume approach has been used and the pressure–velocity coupling is resolved using the simple algorithm. the purpose of this paper is to find that one of the used turbulent models is better for this kind of studies. a structured mesh arrangement with boundary layer mesh...

Reynolds-Averaged Navier-Stokes (RANS) methods have become an important design tool in aerospace industry. Turbulence models, which are required for closure of the RANS equations, are a substantial component in these methods. Several flow regimes exist where the accuracy of flow predictions depends strongly on the turbulence model used. Turbulence has a major influence on the growth rate of bou...

Modeling the structure of molecular clouds depends upon good methods to statistically compare simulations with observations in order to constrain the models. Here we characterize a suite of hydrodynamical and magnetohydrodynamical (MHD) simulations of supersonic turbulence using an averaged wavelet transform, the ∆-variance, that has been successfully used to characterize observations. We find ...

The method of continuous casting of steel is now often used in the metallurgical industry, due to the increasing demand for the production of high – quality steel. An important device of continuous casting machine is the tundish, in which a stabilized steel flow has a crucial effect on the quality and efficiency conditions of the continuous casting process. In this study fluid flows in a six – ...

The aim of this paper is to fully analyze the effects of free space optical (FSO) communication links on the estimation performance of the adaptive incremental networks. The FSO links in this paper are described with two turbulence models namely the Log-normal and Gamma-Gamma distributions. In order to investigate the impact of these models we produced the link coefficients using these distribu...

Theoretical approaches to low-frequency magnetized turbulence in collisionless and weakly collisional astrophysical plasmas are reviewed. The proper starting point for an analytical description of these plasmas is kinetic theory, not fluid equations. The anisotropy of the turbulence is used to systematically derive a series of reduced analytical models. Above the ion gyroscale, it is shown rigo...

The basic science of turbulence has been known for many years, yet the knowledge has hardly become a part of operational aviation turbulence forecasting. The history of turbulence forecasting, which has primarily concentrated at elevations above the boundary layer, has been an amalgamation of empirical rules of thumb and forecaster intuition, not of strong theory and conceptual models. Turbulen...