Data assessment of two ERCOFTAC transition test cases for CFD validation

Turbulence model developers rely on established databases to benchmark advances in turbulence closure methods for Computational Fluid Dynamics (CFD). The European Research Community on Flow, Turbulence and Combustion (ERCOFTAC) provides databases to benchmark different flow regimes. Sub-group 5 of the Special Interest group of Ercoftac (SIG10) on Transition Modelling manages experimental realflow data to validate the predictive capabilities of transition codes. With experimental data, there is a legitimate expectation for the database user to apply some judgment to overcome acceptable accuracy and consistency issues in the dataset. This work aims to document some of the precautions that are required to interpret and use the Ercoftac dataset to calibrate CFD codes. This paper aims to demonstrate the use of the Ercoftac database to validate a two-dimensional CFD transitional solver, giving more details of the approach adopted, and how to use the Ercoftac experimental data to generate the inflow condition, and in doing so to inform the community on the consistency of the information in this dataset by testing it for the known trends in the mean velocity components and their statistical fluctuations. The objectives are to expose some limitations of the dataset and to evaluate the performance of the RANS transition model implemented in the in-house code Cosmic at the University of Leicester. Velocity measurements from two boundary layer test cases under zero pressure gradient are considered.