Ansys has released the Immersed Boundary module for its FLUENT 12.0 software. Developed jointly with Cascade Technologies, the module dramatically reduces the amount of time needed for fluid flow simulations and provides fast results by directly addressing challenges associated with meshing. This first release supports the physical models and boundary conditions needed for modelling low-speed external aerodynamics and automotive front-end airflows.
A conventional fluid dynamics simulation starts with the transfer of CAD data to a grid-generation package, in which a surface mesh and then a volume mesh are generated before the simulation can be set up and the solution run. The effort and time required for such pre-processing tasks can be significant. For example, in cases with complex or dirty geometry that require CAD cleanup, this part of the process may take 50 percent to 90 percent of the total time required for the simulation. The Immersed Boundary module addresses such issues by providing a rapid, automated, preliminary design approach.
Fluid flow simulations using the Immersed Boundary module for Ansys FLUENT 12.0 software start with the surface data of the simulation geometry in the STL file format, which is commonly used in rapid prototyping and computer-aided manufacturing. This CAD geometry does not need to be clean, does not require smooth surfaces or geometry connectivity, and may contain overlapping surfaces, small holes and even missing parts. The simulation geometry is meshed automatically.
Mesh refinement also is carried out automatically after specifying the desired resolution on the boundaries, ensuring the accuracy required for preliminary design evaluation. Using the Immersed Boundary meshing technique greatly reduces the amount of time spent preparing the geometry for meshing and creating the mesh.