We discuss averaged turbulence modeling of multi-scales of length for an incompressible Newtonian fluid, with the help of the maximum information principle. We suppose that there exists a function basis to decompose the turbulent fluctuations in a flow of our concern into the components associated with various spatial scales and that there is a probability density function f of these fluctuatio...

A mathematically defined Wigley hull form is used to investigate the application of a commercial CFD code in prediction of the total resistance and its components from tangential and normal forces on the hull wetted surface. The computed resistance and wave profiles alongside the hull were compared with experimental observations for six different Froude numbers to validate the simulations. The ...

Traditionally, ocean upwelling has been studied mostly from observational data and analytical models of simpliied ow situations. In many areas of (geophysical) uid dynamics, numerical analysis has gradually gained importance and caught up with, if not bypassed, experimental simulations or observations. But, recent laboratory experiments show the very complicated nature of upwelling fronts and i...

Aims. We provide a consistent theory of the tachocline confinement (or anisotropic momentum transport) within an hydrodynamical turbulence model. The goal is to explain helioseismological data, which show that the solar tachocline thickness is at most 5% of the solar radius, despite the fact that, due to radiative spreading, this transition layer should have thickened to a much more significant...

The general flow structure over transverse aeolian dunes is now well documented through both field studies and wind tunnel experiments. Research on windward (stoss) slopes of dunes is extensive and has recently been complemented by research on the lee-side flow structure. However, a number of technical deficiencies in wind tunnel instrumentation and a lack of detailed resolution in and appropri...

Turbulent separated flows around an airship-like geometry (a prolate spheroid 6:1) are investigated using three turbulence modelings based on statistical and Large Eddy Simulation (LES) approaches. The turbulence models used in the simulations are a standard high Reynolds k–ε model, a Smagorinsky LES model and a variational multiscale LES one. The flow of interest is characterized by a relative...

In this report several modern turbulence modeling techniques with applications to high-Reynolds number external flow are critically evaluated. Fully developed turbulent channel flow and the flow past the Ahmed body with a slant angle of 25◦ are both used to benchmark several LES and DES models for turbulence closure. Channel flow is simulated at two different Reynolds numbers and both the LES a...

This study makes the first attempt to use the 2/3-order fractional Laplacian modeling of Kolmogorov -5/3 scaling of fully developed turbulence and enhanced diffusing movements of random turbulent particles. A combined effect of inertial interactions induced diffusivity and the molecular Brownian diffusivity is considered the bi-fractal mechanism behind multifractal scaling of moderate Reynolds ...

This study makes the first attempt to use the 2/3-order fractional Laplacian modeling of enhanced diffusing movements of random turbulent particle resulting from nonlinear inertial interactions. A combined effect of the inertial interactions and the molecule Brownian diffusivities is found to be the bi-fractal mechanism behind multifractal scaling in the inertial range of scales of moderate Rey...

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...