Conservation of mass, momentum, energy, helicity, and enstrophy in fluid flow are important because these quantities organize a flow, and characterize change in the flow’s structure over time. Thus, if a simulation of a turbulent flow is to be qualitatively correct, these quantities should be conserved in the simulation. However, such simulations are typically based on turbulence models whose c...

in this paper, inflow turbulence effects on the flow wake parameters around a naca0012 airfoil at zero incidence angle and reynolds number of 38,700 were investigated. various turbulence promoter networks were used to achieve turbulence intensity of 5% and 6%. experiments have been conducted for three different turbulence intensities in which mean velocity parameters, turbulence intensity, freq...

A review of existing basic turbulence modeling approaches reveals the need for the development of unified turbulence models which can be used continuously as filter density function (FDF) or probability density function (PDF) methods, large eddy simulation (LES) or Reynolds-averaged Navier–Stokes (RANS) methods. It is then shown that such unified stochastic and deterministic turbulence models c...

One of the newest of viscoelastic RANS turbulence models for drag reducing channel flow with polymer additives is studied in different flow and rheological properties. In this model, finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive model is used to describe the viscoelastic effect of polymer solution and turbulence model is developed in the k-ϵ-(ν^2 ) ̅-f framework. The geome...

This paper describes a study of the self-sustaining process in wall turbulence. The study is based on a second order statistical state dynamics model of Couette flow in which the state variables are the streamwise mean flow (first cumulant) and perturbation covariance (second cumulant). This statistical state dynamics model is closed by either setting the third cumulant to zero or by replacing ...

Flow separation at water intake is the main cause of head loss and flow discharge reduction. As a result, study of shape and size of separation is very essential when designing an optimum water intake. Water intake is normally built with a 90 degree angle to the main channel flow direction. However, the flow structure in this type of water intake consists of large separation size along with ...

We review the main properties of shell models for magnetohydrodynamic (MHD) turbulence. After a brief account on shell models with nearest neighbour interactions, the paper focuses on the most recent results concerning dynamical properties and intermittency of a model which is a generalization to MHD of the Gledzer-Yamada-Okhitani (GOY) model for hydrodynamic. Applications to astrophysical prob...

Lindborg et al. (2010) claim that the apparent spectrum power law E(k) ≈ k−3 on scales ≥ 600 km obtained with the help of commercial jetliner trajectory deviations (GASP and Mozaic databases) could not be brought into question (Lovejoy et al., 2009a), because this spectrum corresponds to “a well known theory of quasi-geostrophic turbulence developed by Charney (1971)”. Lindborg et al. (2010) al...

To explore the character of the underlying transport in plasma turbulence, we have followed the motion of pseudo-particle tracers during the nonlinear evolution of three-dimensional turbulence models. These calculations have been performed for three different turbulence models and are associated with resistive interchange, resistive ballooning, and ηi modes, respectively. The finite-scale Lyapu...

Simple fluids such as gases and liquids are the result of collisions between molecules. More complex fluids, such as granular flows and colloidal suspensions (non-Newtonian fluids), result from the more complex collision (or interaction) behaviors of their constituent particles. In this paper it is demonstrated that collision rules can be constructed for large chunks of fluid material (eddies) ...