A two dimensional model is introduced to study pattern formation, secondary instabilities and the transition to spatiotemporal chaos (weak turbulence) in parametric surface waves. The stability of a periodic standing wave state above onset is studied against Eckhaus, zig-zag and transverse amplitude modulations (TAM) as a function of the control parameter ε and the detuning. A mechanism leading...

The current work presents the numerical prediction method to determine small-scale propeller performance. The study is implemented using the commercially available computational fluid dynamics (CFD) solver, FLUENT. Numerical results are compared with the available experimental data for an advanced precision composites (APC) Slow Flyer propeller blade to determine the discrepancy of the thrust c...

The University of Virginia has been utilizing CFX series software to design and analyze implantable rotary blood pumps for several years. Besides the basic computational fluid dynamics (CFD) calculations and simulations of fluid field for blood pumps, several advanced CFD models were used which were relevant to the analysis of blood pumps or magnetic bearings. A Lagrangian Particle Tracking stu...

Gravity currents are very common in nature and may appear in rivers, lakes, oceans, and the atmosphere. They are produced by the buoyant forces interacting between fluids of different densities and may introduce sediments and pollutants into water bodies. In this study, the hydrodynamics and propagation of gravity currents are investigated using WISE (Width Integrated Stratified Environments), ...

A numerical simulation of flow and heat transfer in a ventilated concrete dry storage cask system–17 (VSC–17) is performed and results compared with experimental data to assess the validity of the computational approach. The measurements of steady state temperature distributions on the cask surface, concrete surface, air flow channels, and fuel canister guide are available. Numerical simulation...

This paper presents an original approach regarding the application of sweep to rotating blade cascades. The justification for swept blades is given by its consequence, i.e. a reduction of local velocity (usually from supersonic/ transonic to subsonic regimes) such that the losses due to shock waves and/or boundary layer displacement and/or followed by reattachment are minimized. As study cases ...

in this paper, the accuracy of k- and k- turbulence models in super sonic boundary layer capturing of smooth/rough flat plates have been comprehensively investigated. among these investigations, some sorts of sensitivity analysis, including change in turbulence model, generated-grid density, near wall affects, c magnitude (for boundary layers generated on smooth flat plates), and change in c...

We construct a magnetic helicity conserving dynamo theory which incorporates a calculated magnetic helicity current. In this model the fluid helicity plays a small role in large scale magnetic field generation. Instead, the dynamo process is dominated by a new quantity, derived from asymmetries in the second derivative of the velocity correlation function, closely related to the ‘twist and fold...

For the investigation of stratified two-phase flow, two horizontal channels with rectangular crosssection were built at Forschungszentrum Rossendorf. The channels allow the investigation of air/water co-current flows, especially the slug behaviour, at atmospheric pressure and room temperature. The test-sections are made of acrylic glass, so that optical techniques, like high-speed video observa...