The Naval Surface Warfare Center (NSWC) has successfully simulated the Coanda effect using computational fluid dynamics (CFD) – which may help improve low-speed maneuverability of ships and planes. The engineers demonstrated that by blowing air out of a strategically located slot in an airfoil, the rear stagnation point could be moved further aft along the trailing edge of the airfoil, thereby increasing lift. The military has worked on a number of potential applications for this effect, such as making it possible for submarines moving at low speeds to make sharp turns. The key to the advance made by the NWSC was the use of the Reynolds stress model for predicting turbulence in the jet, which the research shows is far more accurate than the more common k-epsilon models.

The Naval Surface Warfare Center is the principal Navy resource, national focal point and international leader in surface and undersea vehicle science, ship systems and related maritime technology. A major technical component of the Naval Sea Systems Command, the Division is a source of innovative technology for other national priorities such as environment, energy and transportation. The Division is responsible for research, development, test and evaluation, fleet support, and in-service engineering for surface and undersea vehicles, including hull, machinery and electrical systems, and propulsors. It conducts logistics research and development, and provides support to the Maritime Administration and the maritime industry. The technical leadership areas of the Carderock Division include materials, structures, ship protection systems, vehicle concepts, hydrodynamics, acoustic and electromagnetic signatures, environmental protection systems, and logistics.

Stephen Labbe, chief of the Applied Aeroscience and Computational Fluid Dynamics branch at Johnson Space Center, said last week that the shuttle experienced an unusual change in forces on its left wing between the shedding of two pieces of observed debris. Despite the presumed damage, he said, the orbiter "executed a perfectly nominal roll reversal," or banking of the wings, about two minutes after the two pieces of debris were shed. Significant damage, he said, can create "locally a very high pressure that is on the lower surface of the wing and starting to push up on the wing."

Labbe and other NASA officials told the board that wind tunnel tests and computational studies simulating various types of damage to the left wing have yet to provide a coherent explanation for all of the forces Columbia experienced before it broke apart. The teams plan to do additional studies that mimic more severe damage than originally postulated, including the loss of multiple leading edge panels rather than just one.

Investigators face a complex task with computational tools they have had to develop as they go. There are no good models, officials said, for what happens when hot gases penetrate a shuttle wing and pass through existing vents or directly attack aluminum spars and ribs.

CFX-5 Live

For those unfamiliar with CFX-5, this demonstration illustrates the superior CFD technology available through CFX-5. Features of CFX-5 to be demonstrated include grid adaption, parallelization set-up and CFX Expression Language.
April 24 at 2 pm EDT
May 22 at 2 pm EDT
June 26 at 2 pm EDT

Introduction to CFX-BladeGen

CFX-BladeGen is a specialized easy-to-use three-dimensional software tool for the rapid design of rotating machinery components. It can be used to design axial, mixed flow and radial blade components in applications such as pumps, compressors, turbines, turbochargers, blowers and fans. A unique feature of the software is its 'Plus' module which enables rapid 3-D viscous flow screening of the design through an embedded and fully automated computational fluid dynamics (CFD) solver.
April 30 at 2 pm EDT
June 12 at 2 pm EDT

Please join us! For more information or to register visit the CFX Website.

In recent tests using CD adapco Group's STAR-CD software for CFD simulation, the SGI Altix 3000 family demonstrated performance and scalability comparable to some of today's best UNIX systems.

"SGI continues to advance their HPC leadership in CFD with the introduction of the new SGI Altix 3000 server. Working together, SGI and CD adapco have achieved several breakthroughs in parallel scalability with STAR-CD simulations," said Peter S. MacDonald, president of adapco and general manager of CD.

With the launch of ICEM CFD version 5 expected later this year now is an excellent opportunity to see what's coming and to discuss your future requirements directly with ANSYS / ICEM CFD Engineering.

The meeting will cover new features and products as well as user presentations and will give you the chance to meet fellow ICEM users from all over Europe.

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For all vehicles, ranging from small passenger vehicles to commercial buses and trucks, reducing air drag is one of the most efficient ways of improving fuel economy. For example, a 5% improvement in drag for a typical diesel engine heavy tuck, which can simply be achieved by improving the design of the wing mirrors, can result in fuel savings of around 500-1000 litres/year for a typical 150,000 km annual highway driving. On the other end of the scale, in motor racing fuel saving might not be the number one priority, but reaching very high speeds certainly is. To propel a typical Class 1 ITC racing car at 300km/h, around 30 kW of additional power is required for a car with drag coefficient of 0.40, compared to one with 0.36. And when you are operating at the limit of your engine, this can make the difference between winning or losing.

One of the first commercial systems to tackle the complex world of external aerodynamics simulation is es-aero. This is a knowledge-based expert system developed by the CD adapco Group and based on the CFD code STAR-CD. The knowledge and expertise embedded in the system comes from many man-years of knowledge and experience gained through the running and analysis of hundreds of external aerodynamic cases, by both the CD adapco Group and its clients and partners.

To read this article in full and discover other Expert Systems from CD adapco Group, visit their website.