The following is an excerpt from a chat with experts at AVL regarding their new eFAME service:
AVL Expert-Chat, 26th November 2002 - eFAME
Q: Could you explain, how the meshing procedure with eFAME looks like? Legolas
A: Dear Legolas, thank you for being with us today at our chat-event on our new online meshing service e-fame. Before we jump into discussion we would like to briefly introduce ourselves: Ferdinand Kickinger: Since 4 years I am working on advanced meshing tools and project leader for e-fame. Peter Blahowsky: I am responsible for global business development of the business unit AST and am with AVL since 1990. We are inviting you to join an intensive discussion on how CFD and FEM meshing tasks can be simplified. The meshing procedure works as follows: first you have to create with CAD package an STL-file, which describes your computational domain. Then you submit this file (zipped) to our e-fame server then you will receive after the server has meshed your problem, a meshing report, which outlines the quality size and important details visually. If you like what you see, you may order the actual mesh at the specified rate. The meshing server will then transfer the file to you. Sound simple - doesn't it?
Q: Your service sounds quite interesting. How long will it take to get the meshing report? kadmos
A: We expect in the beginning at 24 hours response time. Ones we have reached our planned server configuration respond time should be in the range of hours.
Q: What kind of meshes do you generate? Sue
A: Dear Sue, thanks for this question. The meshes generated by the e-fame service contain different types of cells. These types are hexahedrons, prisms, pyramids and tetrahydrons. This meshes are typical called 'hybrid-meshes'. The flexibility of Hybrid-meshes allows us to provide high quality meshes, which are strongly hexahedron dominated. A typical mesh contains about 80% hexas.
Q: What are the specific advantages of your meshing software? Why should I try eFAME? kadmos
A: Hello Kadmos, first we have to differentiate between 2 things: 1) our meshing software FAME, which is part of our CFD solution packages or licensed separately or 2)our online meshing-service, which is based on FAME. The advantage of using e-FAME is the fully automized mesh generator, which is producing the before mentioned hybrid meshes. The benefit of using e-FAME is, that the user does not need to worry about software licensing, but can submit risk free a meshing problem, so why should you not use e-FAME?
Q: Hybrid meshes - this sounds promising. What is the advantage of these hybrid meshes in contrast to tetrahydrons? Legolas
A: First of all hybrid meshes reduce the number of cells typically by a factor of 3 compared to tetahedral meshes with the same special resolution. This reduction in mesh size does not compromise mesh quality. With excellent mesh quality and hex-dominated meshes the numerical accuracy of CFD programs is ensured.
Q: What about confidentiality? Legolas
A: The problem submitted by the users of the e-FAME meshing service will be treated as absolutely confidential. Only the e-FAME administrator and his team had access to the files. Be aware that the data during submission is not encrypted. If you wish, final meshes can be transferred encrypted to you.
Q: How can I check the quality of the mesh for my submitted problem? Sue
A: Mesh quality is defined by a number of metrics such as warpage, skewness, aspect ratios, etc. All of these checks will be performed after the meshing process of your problem and will be part of the meshing report send to you. Additionally will be provide visual depictions of the mesh, which will allow you charge the usefulness of the mesh. Of course we are open to add additional metrics if user find supplied data insufficient. Sample meshes can be downloaded under meshing.avl.com, where you can check yourself with your favorite CAE software package.
Q: Which CFD solver can handle eFAME meshes, which interfaces do you provide for the data transfer to the solvers and which solver do you recommend Paul
A: Dear Paul, thanx for joining the session. Basically all commercially available CFD solvers can handle meshes produced by e-FAME. For testing this ability you may download the sample meshes as indicated before. The data transfer of meshes is done via the commonly used universal file format. Of course we recommend as CFD solvers the AVL solutions SWIFT/FIRE as we have taken special care with our numerical algorithm to achieve highly accurate solutions in shortest possible time. Our solvers are based on a fully flexible polyhedral discretization schemes, which fits perfectly to hybrid meshes.
Q: OK, so you told me to try eFAME because it's license-free. But what is the price for doing so? How much is it to have a mesh produced online? kadmos
A: Yes using e-FAME is license free. The price for generating a mesh depends on the following factors: number of surface patches, number of generated cells and required CPU time. In principle the price is depending on the complexity of the submitted meshing problem. We suggest you to submit your meshing problem.
Q: Is it possible to use these hybrid meshes for FEM? Legolas
A: Based on the requirement that your FE software is able to handle hybrid meshes the generated e-FAME meshes are very well suited for solving FE problems. At AVL we have successfully used meshes generated by this mesh generator for crankshafts, pistons, conrods and complete engine block configurations.
Q: What is the meshing algorithm behind efame? Sue
A: Well, the algorithm behind e-FAME is based on an octree spatial division process. By using a conformal local refinement process to resolve all geometrical details a background mesh will be created and thereafter mapped to the supplied surface. Afterwards the mesh is smoothed and a boundary layer is added. You will find more details on our WebPages. Feel free to send us an email at firstname.lastname@example.org for further discussions.
Q: Is there any limit regarding mesh size? Paul
A: No Paul, there is no limitation in respect to mesh sizes. One just has to be aware of increasing files sizes and us increased transfer rates. The only limit we currently have in the start up phase is that stl-files are limited to 10MB file size in zipped format. If this is a problem, please contact our meshing administrator.
Q: To be honest this service sounds promising, but I wonder, when it be available? (considering previous release delays) Legolas
A: As a matter of fact, the e-FAME service is online right now and you may submit your meshing problem immediately.
Q: I think eFAME is a very good idea - do you plan to extend you services and will you provide full CFD solutions in the future? Michael
A: Dear Michael, yes of course, we are planning to provide a full portfolio of CFD related online services in the near term future. We start with e-FAME as meshing is for many CFD engineers the major bottleneck of today. Providing a solver solution is a natural next step.
Q: Is there a (free) viewer available? Sue
A: Sue, within the next two months there will be a free viewer for downloading available on the e-FAME web area. With this viewer it will also be possible to define additional criterias which will influence the meshing process in particular the refinement levels and areas. This means, you will be able to define the absolute mesh width in predefined areas and thus overrule the automatically chosen mesh-width. The result is a customized mesh which fits your requirements.
Dear Chat Participants, thank you for your active contributions at our chat event. We hope you personally will try our new e-FAME meshing service soon and let us know your feedback. If you have further questions or commends fell free to send a mail to us or to email@example.com Peter Blahowsky Ferdinand Kickinger