Fabric analysis of internally unstable soils: (Abstract)

Planar velocity & concentration measurements in a magnetic micromixer with interface front detection

Mixing is often a challenge in small scales and substantial research effort is focused on designing high performance micromixers. Active micromixers use various forces to enhance mixing efficiency. Among these, magnetic forces are often preferred as they are non-contact and do not require manufacturing of small moving parts in the microchannel....

Hydrodynamic Instabilities in Czochralski Process of Crystal Growth

This paper deals with axisymmmetry breaking instabilities in Czochralski process of crystal growth. Numerical linear stability analysis was carried out using the axisymmetric bulk flow model. Stability diagrams of critical Grashof numbers Grc and frequencies ?c dependent on aspect ratio alpha(=height/radius), 0.4 =< alpha =< 1.0 and Prandtl...

Flame front capturing/tracking schemes for compressible and incompressible reactive flow

We present hybrid capturing/tracking methods for the simulation of turbulent premixed flames in meso- and large-scale geometries. Such schemes resemble a tracking schemes in that the flame front is explicitly computed and propagated using a level set method. The flame-flow-coupling uses in-cell-reconstruction. In cut cells, burnt and unburned...

Premature decay of wake vortices with Differential- and Oscillating Flap Setting

This paper gives an overview of the research on wake vortex decay using Differential Flap Setting (DFS) and Oscillating Flap Setting (OFS). The concept of DFS deals with the small deflection of flaps and elevator to produce additional vortices which interacts with the vortices from wing, elevator, flaps and wing-body-junction. Numerical...

Direct Numerical Simulation and Large-Eddy Simulation of wake vortices: Going from laboratory conditions to flight conditions

This paper aims at presenting DNS and LES as applied to the simulation of vortex wakes: in laboratory conditions (moderate to medium Reynolds numbers) and up to real aircraft conditions (high to very high Reynolds numbers). Only incompressible flows are considered. DNS and LES are able to capture complex 3-D physics provided one uses high...

Effects of fluid-structure interaction on the trailing-edge noise

In the present study, the effects of fluid-structure interaction (FSI) on the trailingedge noise are numerically investigated, particularly for the cases of wake instability and Karman vortex shedding. The trailing-edge is modelled as a flat plate with an elastic cantilever end and its flow-induced vibration is solved by an eigenmode analysis...

The magnetorotational instability in cylindrical Taylor-Couette flow

We consider the flow of an electrically conducting fluid between differentially rotating cylinders, in the presence of an externally imposed magnetic field. Several codes are presented to study this problem, consisting of linear eigenvalue and nonlinear time-stepping programs. Depending on whether the magnetic Reynolds number is small or large,...

Influence of Coriolis forces on the dynamic of a turbulent jet

The influence of Coriolis forces is studied under realistic conditions on a jet in atmospheric medium. Under the Boussinesq approximation, the relative thickness of the jet defines a small parameter in the flow. This parameter governs the asymptotic expansion of the analysis. Using a linear spectral approach, two-point closure correlation...

Simulations of merging in a two co-rotating vortex system

All aircraft shed, as a consequence of lift, a wake ("vorticity sheet") which rapidly rolls up into several concentrated vortices at a distance of a few chords behind the trailing edge of the wing. A simplified configuration has been adopted to understand the physical mechanisms characterizing the merging process in the extended near-field. This...

Large Eddy Simulation of Bifurcating and Transitional Suddenly Expanded Flows

Implicit Large Eddy Simulation (ILES) using high-resolution methods have been employed in the investigation of bifurcation and transition of flow through three dimensional suddenly-expanded channels. ILES refers to high-resolution methods employed in spatially under-resolved simulations of turbulent flows without the need to resort to turbulence...

A stable pressure-correction algorithm for low-speed turbulent combustion simulations

To perform accurate LES-calculations of low Mach number flows with non-premixed combustion, an efficient, robust and accurate algorithm is needed. So-called pressure-correction methods are efficient algorithms for this purpose. Those methods are well elaborated for flows with constant density. However, in non-premixed combustion simulations, the...

CSF model performance for Rayleigh-Taylor instability

In the present study, the surface tension is introduced as volume forces according to the continuum surface force (CSF) model [1] using the surface tension coefficient and the mollified volume fraction (color) function. The latter can be taken in the first approximation as the volume fraction defined numerically due to (possible) smoothing of...

Saffman-Taylor instability and interface capturing by semi-Lagrangian level set method

This work presents some results concerning the interface evolution of two imiscible fluids flowing inside an isotropic porous medium in a typical viscous instability problem, known as the Saffman-Taylor instability. This involves the application of an iterative parallelizable graph based algorithm coupled with a semi-Lagrangian level set...