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The results presented at the Second AIAA High-Lift Prediction Workshop, using the flow-solver Edge, are summarized for the DLR, German Aerospace Center F11 model. A comparative study of the results, using three turbulence models, is carried out, including the Spalart-Allmaras model, an explicit algebraic Reynolds-stress model, and a curvature correction to the explicit algebraic Reynolds-stress model. The comparisons include a grid-convergence study on a simplified model without slat- and flap-track fairings, and polar calculations including the fairings. The grid-convergence study shows relatively small differences due to different grid resolution and turbulence models, but the differences are larger than those obtained in the first workshop for the NASA trap wing. The prediction has fairly large discrepancies from experimental measurements at low Reynolds numbers for which the computations were carried out assuming fully turbulent flow. The explicit algebraic Reynolds-stress model (with or without curvature correction) tends to exaggerate flow separation and to underpredict the lift, as compared to the experiment. The Spalart-Allmaras model, on the other hand, overpredicts the lift at higher incidences. At the higher Reynolds number, the predictions agree well with the experimental measurements for different turbulence models. The curvature correction to the explicit algebraic Reynolds-stress model has an insignificant effect on the computed results in comparison with the explicit algebraic Reynolds-stress-model predictions. [ABSTRACT FROM AUTHOR]

Results carried out for the 4th AIAA Drag Prediction Workshop with the flow solver Edge are summarized. Simulations have been carried out for wing-body-tail configurations with three horizontal tail incidences and for one tail-off configuration. The computations consist of a grid-refinement study and a downwash study with polar calculations to explore the trimmed condition and delta effects. An investigation of the sensitivity to the grid and turbulence model is carried out from calculations on two sets of unstructured grids with three turbulence models, including the explicit algebraic Reynolds stress model, the k-ω SST model, and the Spalart-Allmaras model. The grid-refinement study, for which the flow is attached, shows rather small differences due to different grids and models. The major difference is obtained from the turbulence models where about 10 drag counts between the highest and lowest drag values are predicted, respectively, by the explicit algebraic Reynolds stress model and the Spalart-Allmaras model. The difference between the two sets of grids is only about two drag counts. The polar calculations in the downwash study also show rather small differences in which the same tendency for the drag prediction is observed as in the grid-refinement study. The largest differences between the solutions are due to different turbulence models and observed at the highest angles of attack, where the flow starts to separate after the shock on the wing. [ABSTRACT FROM AUTHOR]

An embedded large-eddy-simulation modeling approach is explored and verified using the partially averaged Navier--Stokes model as a platform. With the same base model, the turbulence-resolving large-eddy simulation region is embedded by setting the partially averaged Navier-Stokes model coefficient to fk < 1 as distinguished from its neighboring Reynolds-averaged Navier-Stokes region, where fk = I is specified. The embedded large-eddy simulation approach is verified in computations of a turbulent channel flow and a turbulent flow over a hump. Emphasis is placed on the impact of turbulent conditions at the Reynolds-averaged Navier-Stokes/large-eddy simulation interface using anisotropic velocity fluctuations generated from synthetic turbulence. The effect of the spanwise size of the computational domain is investigated. It is shown that the embedded large-eddy-simulation method based on the partially averaged Navier-Stokes modeling approach is computationally feasible and able to provide reasonable turbulence-resolving predictions in the embedded large-eddy simulation region. The wall-adapting local eddy- viscosity model is also evaluated for the hump flow and it is found that its performance is worse than that of the the low-Reynolds-number partially averaged Navier-Stokes model when the results are compared with experiments. [ABSTRACT FROM AUTHOR]

Numerical investigations are reported on the DLR-F6 wing -body configuration with and without fairing. The configurations have been adopted as test cases for the Third AIAA Drag Prediction Workshop. The addition of the fairing is to eliminate the flow separation bubble in the junction between the wing trailing edge and the fuselage. The computations have been carried out using two groups of unstructured grids with different sizes. In addition to the effect of incidences, studies of grid convergence have also been performed. The computational fluid dynamics solver Edge is used for the investigation. The calculations confirm that the flow separation can be removed in the wingfuselage junction with the fairing. For this configuration, the results obtained with the two groups of grid are very similar. Without fairing, however, one group of grids has pronounced a lower lift and produced a more extended trailing-edge separation. Because no experimental data are available for the flow condition as specified in Drag Prediction Workshop-3, additional calculations have been carried out with the clean wing-body configuration at the Drag Prediction Workshop-2 Reynolds number to validate the numerical results against available experimental data. Very good agreement is obtained, in particular, for the global forces and moments. The calculation indicates that, as compared with experimental data, the grid which predicts a relatively large separation region provides improved predictions. [ABSTRACT FROM AUTHOR]