On August 1st I visited CFX Engineering Software in Waterloo, Ontario Canada and was given previews of several upcoming software packages from this tier-1 CFD vendor.

The Waterloo office is home to CFX's software development teams for CFX-TASCflow, CFX-TurboGrid, CFX-Post and the largest portion of the CFX-5 team, in addition to a portion of the sales and support group for North America. There are approximately 60 employees in the office, half of whom are involved in software development.

My visit was hosted by Dr. Jeff Van Doormaal, product development manager for CFX-TurboGrid, CFX's grid generation software tool for turbomachinery applications.

Note: For your chance to ask CFX Engineering Software about CFD development, add your question to this discussion.

Dr. Davis is one of the people who answers the “will it fly right” question when confronted with next generation modifications. He helps assure that any modifications to aero/propulsion capabilities, airframe additions including antennas, and other changes maintain and enhance performance.

Dr. Davis and his team gauge adaptations on the computer, using two remarkable programs (among other tools): Gridgen and Overflow. Gridgen is Pointwise Inc.’s grid generation and pre-processing CFD enabling bridge connecting computer aided design (CAD) software and CFD solvers such as Overflow, Fluent, STAR-CD, and CFX. The program generates hexahedral, tetrahedral, and hybrid (prisms and pyramids) meshes, reads geometry from CAD systems, and includes meshing tools and direct solver interfaces. Overflow is a Navier-Stokes flow solver that uses single block grids or Chimera overset (structured) grid systems. Chimera overset grids are body-fitted hexahedral grids around each component. They can overlap each other instead of requiring exact point-to-point interface matching like traditional structured grids. This makes the engineer’s grid generation task faster and easier while maintaining accuracy.

Caterpillar aims to design and manufacture superior hydraulic components, supported by high quality system maintenance and service, and its vehicles are renowned for their performance and reliability. So when it became clear that there was a problem with some of its larger vehicles, Caterpillar pulled out all the stops to find a solution.

For the past 50 years, Turboinstitut has been involved in the research and development of hydraulic machines. CFD has become an indispensable tool in our activities, and this is especially true for our turbine refurbishment projects, which are usually realized entirely with CFD. Using CFX-TASCflow, we can analyze the flow throughout the whole turbine, taking into account the stator-rotor-draft tube interaction and avoiding potentially inaccurate boundary conditions between components. However, compared to individual simulations for each part, such calculations require large models and long run times. Separate analysis is much faster, but it is essential to know when coupled analysis must be performed and what are the differences between separate and coupled analyses. At the Institute, by comparing results for coupled and separated calculations, we have found that the separate analysis usually overpredicts flow energy losses in all turbine parts and only coupled analysis is suitable for accurate prediction of turbine efficiency.

The FLUENT flow solver is used in the two following applications, however, the optimization process is independent from the choice of flow solver. Other applications have been developed using ICARE, a dedicated solver for free surface flows in viscous fluid around a ship hull.

In order to extend the benefits of CFD to product engineers, CFD meshing must be enhanced through specialized meshing applications which automate the mesh generation process and replace CFD jargon with terminology familiar to designers. In this article I will describe application-specific CFD meshing and a method for creating such applications.