The Ultrasonic transit time method is well established to measure the volumetric flow rates of liquids and gases. In most applications the measured flows are turbulent. The ultrasonic measurement technique has advanced to a level of accuracy where the turbulence of the measured media is the main source of fluctuations in the measured flow value. Experiments on flowmeters with different diameter...

A brief review of the literature is provided on the characteristics of marine currents and the approaches used for simulating tidal turbines. The feasibility of using CFD models to simulate time-dependent turbulent flow around a tidal turbine is then explored. Two different approaches for specifying the structure of the turbulent inflow conditions in CFD models are compared: the von Kármán spec...

The program package UG provides a software platform for discretizing and solving partial diierential equations. It supports high level numerical methods for unstructured grids on massively parallel computers. Various applications of complex up to real-world problems have been realized, like Navier-Stokes problems with turbulence modeling, combustion problems, two-phase ow, density driven ow and...

We discuss the first two months of low altitude atmospheric turbulence at the Antarctic site of Dome C. Using a mini-SODAR, the first 890m of the atmosphere were sampled. It was found that between 9 Feb and 17 Apr 2003, the turbulence was concentrated below a 120m boundary layer that exhibited a clear diurnal cycle. This boundary layer height is less than half as thick as that at the South Pole...

One of the more promising recent approaches to turbulence modelling is the Variational Multiscale Large Eddy Simulation (VMS LES) method proposed by Hughes et al. [Comp. Visual. Sci., vol. 3, pp. 47-59, 2000]. This method avoids several conceptual issues of traditional filter-based LES by employing a priori scale partitioning in the discretization of the Navier-Stokes equations. Most applicatio...

Based on three-dimensional simulations of the Braginskii equations we show that for typical plasmaedge parameters the saturation of electromagnetic toroidal hi mode turbulence is controlled by the selfgeneration and subsequent annihilation of radial magnetic field perturbations. This should be contrasted with the electrostatic limit, where the growth of the linear hi mode is terminated by the o...

A significant inward flux of toroidal momentum is found in global gyrokinetic simulations of ion temperature gradient turbulence, leading to core plasma rotation spin-up. The underlying mechanism is identified to be the generation of residual stress due to the k parallel symmetry breaking induced by global quasistationary zonal flow shear. Simulations also show a significant off-diagonal elemen...

Turbulent fluids are frequently observed to spontaneously self-organize into large spatial-scale jets; geophysical examples of this phenomenon include the Jovian banded winds and the earth’s polar-front jet. These relatively steady large-scale jets arise from and are maintained by the smaller spatialand temporalscale turbulence with which they coexist. Frequently these jets are found to be adju...

In this research, the effect of micro turbulence on the flotation rate of quartz particles was investigated. The maximum particle Reynolds number (Rep) was obtained at 60.25 with a particle size of -500+420 µm, impeller speed of 900 rpm, bubble surface area flux of 10.21 1/s and micro scale turbulence size of 162 µm. When the micro turbulence size was equal to the particle size, ...