Description of a Website Resource for Turbulence Modeling Verification and Validation

The activities of the Turbulence Model Benchmarking Working Group ‐ which is a subcommittee of the American Institute of Aeronautics and Astronautics (AIAA) Fluid Dynamics Technical Committee ‐ are described. The group’s main purpose is to establish a web-based repository for Reynolds-averaged Navier-Stokes turbulence model documentation, including verification and validation cases. This turbulence modeling resource has been established based on feedback from a survey on what is needed to achieve consistency and repeatability in turbulence model implementation and usage, and to document and disseminate information on new turbulence models or improvements to existing models. The various components of the website are described in detail: description of turbulence models, turbulence model readiness rating system, verification cases, validation cases, validation databases, and turbulence manufactured solutions. An outline of future plans of the working group is also provided. The Turbulence Model Benchmarking Working Group, hereafter referred to as the TMBWG, is a committee formed in 2008-2009 under the auspices of the AIAA Fluid Dynamics Technical Committee. The members of the group have interests in turbulence model development, implementation, application, verification/validation, and uncertainty. Here, verification means establishing the correctness of the code in representing the intended model equations (done by systematic discretization convergence tests); validation means establishing the validity of a model via comparison with experiment from the perspective of intended uses of the model. 1 Members of the TMBWG come from both the AIAA Fluid Dynamics Technical Committee and the outside research community. The group has determined that a repository for turbulence model documentation ‐ including verification and validation cases ‐ would be useful to the CFD community. This resource is envisioned to help the aerospace CFD community achieve consistency and repeatability in turbulence model implementation and usage. Early in the life of the TMBWG, surveys were conducted of its members as well as of others in the CFD community, regarding the use of turbulence models in Reynolds-averaged Navier-Stokes (RANS) codes. Summaries of the results are given in the Appendix. For the most part, the survey results were not surprising. Four key points were: (a) existing turbulence models were felt to be reasonably accurate for simple flows, but not for complex flows; (b) there is generally low confidence that consistent results will be obtained when a given model is implemented in multiple codes; (c) even with advances in large-eddy simulation methods, the need for RANS turbulence modeling will likely persist for many years; and (d) improved model documentation and benchmarking are needed to help improve consistency between codes as well as to aid in the verification and validation process. Predicting if and when breakthroughs in RANS turbulence models may be made in the future is impossible, but having a receptive environment for new ideas can help encourage innovation. The committee felt that by making improvements in turbulence modeling documentation as well as by providing a set of consistent benchmark cases, a forum could be established through which new model ideas could be quickly tested and accepted into the CFD