Large-Scale Experiments on the Formation of Surface Vortices with and without Vortex Suppression

Experiments were carried out in a 50-m3 cylindrical tank to determine the influence of strong momentum on the formation of large-scale gas-core vortices. Gas-core lengths were measured for varying volume flow rates and submergence depths. The critical Froude numbers were also determined and the efficiency of different vortex suppressors on the gas-core formation was investigated. The horizontal velocity field inside the vortex core region was additionally recorded using particle image velocimetry. The experimental results were used to verify numerical simulations and compared to vortex models and correlations from literature.German Federal Ministry of Education and Research Project Number 02NUKO23

New portable FELIX 3D display

ABSTRACT An improved generation of our "FELIX 3D Display" is presented. This system is compact, light, modular and easy to transport. The created volumetric images consist of many voxels (volume pixel), which are generated in a half-sphere display volume. In that way a spatial object can be displayed occupying a physical space with height, width and depth. The new FELIX generation uses a screen rotating with 20 revolutions per second. This target screen is mounted by an easy to change mechanism making it possible to use appropriate screens for the specific purpose of the display. An acoustooptic deflection unit with an integrated small diode pumped laser draws the images on the spinning screen. Images can consist of up to 10,000 voxels at a refresh rate of 20 Hz. Currently two different hardware systems are investigated. The first one is based on a standard PCMCIA digital/analog converter card as an interface and is controlled by a notebook. The developed software is provided with a graphical user interface enabling several animation features. The second, new prototype is designed to display images created by standard CAD applications. It includes the development of a new high speed hardware interface suitable for state-of-the-art fast and high resolution scanning devices, which require high data rates. A true 3D volume display as described will complement the broad range of 3D visualization tools, such as volume rendering packages, stereoscopic and virtual reality techniques, which have become widely available in recent years. Potential applications for the FELIX 3D Display include imaging in the fields of air traffic control, medical imaging, computer aided design, science as well as entertainment