Advanced Visual Systems: Solutions: Aerospace: CIRA

Case Study: Italian Aerospace Research Center

The Scientific Visualization Group at CIRA, the Italian Aerospace Research Center founded in 1985, develops innovative techniques and tools to aid researchers and engineers in the Italian and European aerospace industries. The group also supports end-users, both CIRA researchers and industrial users, with application-specific software integration — computational modules, user interfaces and data analysis graphics — resulting in user-friendly simulation systems. CIRA had traditionally used proprietary graphics libraries, the C programming language and public domain user-interface toolkits, but then made the switch to AVS/Express.

"Choosing AVS/Express as our development tool has been a real revolution," says Paolo Leoncini, head of CIRA's Scientific Visualization Group. "We can now focus on real visualization problems rather than on data management, rendering, interaction or portability as we build our end-user applications.

"With AVS/Express, our products will offer an actual scientific added value by incorporating innovative data representations and visualization techniques, properly developed by experts who concentrate mostly on research. Furthermore, AVS will easily enable us to keep our product up-to-date with new computer architectures, graphics platforms, and with computer techniques and technologies, as well as trends such as Web integration."

CIRA has two legacy fluid-flow analysis systems that use multiblock structured grids, both based on Silicon Graphics GL routines for graphics. One, FLOVIS™, is a general-purpose 3D visualization tool that offers the most common data representations and visualization techniques used by researchers and engineers in fluid dynamics and other computation disciplines. The second, NOVA, handles particle tracing (stream lines and streak lines) as a collaborative visualization shared between geographically distant scientists.

CIRA used AVS/Express to endow the second generation of FLOVIS and NOVA with greater flexibility to serve a wider range of applications. CIRA's products are used mostly in the pre-design stage of aerospace project engineering, which involves highly detailed numerical analyses of simulations; AVS/Express can accommodate both the broader set of data sources and the large volumes of information.

As a specific example, the Express-based versions of FLOVIS and NOVA introduce the use of unstructured grids in Computational Fluid Dynamics (CFD). Unstructured grids have traditionally been used in finite element analysis, where the number of grid nodes is relatively low. In CFD, the number of grid nodes can reach the millions. This enhancement will expand FLOVIS's usefulness from aerospace applications into structural analysis and manufacturing process simulation.

"Using AVS/Express allows quick verification of ideas in a pre-development stage. Thus, a developer can choose from a variety of approaches to application development. Application building becomes really flexible with powerful, low-level control on system mechanisms. At the same time, AVS/Express allows us to assemble modules and design the user interface almost interactively. This shortens development time, and lets us more easily maintain our application code," Leoncini said.

The Express-based products also introduce a module for implementing the Line Integral Convolution (LIC) technique for displaying the flow field over a surface in a realistic manner. Although not created by CIRA, this technique was first implemented for unstructured grids by CIRA's Scientific Visualization Group and released with the Express-based upgrade to the CIRA product. This capability has led to effective numerical-experimental comparisons with oil-flow pattern images acquired in wind tunnel tests.

Finally, Express's Web features have made CIRA's visualization system the central component for integrating the institution's Numerical Wind Tunnel simulation system with its many wind tunnels, as well as allowing remote access to the wind tunnels. "With AVS/Expres, we can do this easily by customizing configurations and applications to balance data transfers," Leoncini said.