Summary of Data from the Fifth AIAA CFD Drag Prediction Workshop

Abstract

Results from the Fifth AIAA CFD Drag Prediction Workshop (DPW-V) are presented. As with past workshops, numerical calculations are performed using industry-relevant geometry, methodology, and test cases. This workshop focused on force/moment predictions for the NASA Common Research Model wing-body configuration, including a grid refinement study and an optional buffet study. The grid refinement study used a common grid sequence derived from a multiblock topology structured grid. Six levels of refinement were created resulting in grids ranging from 0.64x10 6 to 138x10 6 hexahedra -a much larger range than is typically seen. The grids were then transformed into structured overset and hexahedral, prismatic, tetrahedral, and hybrid unstructured formats all using the same basic cloud of points. This unique collection of grids was designed to isolate the effects of grid type and solution algorithm by using identical point distributions. This study showed reduced scatter and standard deviation from previous workshops. The second test case studied buffet onset at M=0.85 using the Medium grid (5.1x10 6 nodes) from the above described sequence. The prescribed alpha sweep used finely spaced intervals through the zone where wing separation was expected to begin. Some solutions exhibited a large side of body separation bubble that was not observed in the wind tunnel results. An optional third case used three sets of geometry, grids, and conditions from the Turbulence Model Resource website prepared by the Turbulence Model Benchmarking Working Group. These simple cases were intended to help identify potential differences in turbulence model implementation. Although a few outliers and issues affecting consistency were identified, the majority of participants produced consistent results.

Validation of a near-body and off-body grid partitioning methodology for aircraft aerodynamic performance prediction

“…Some of these outcomes are presented in [25], they include near-field and far-field components. Since the grid converged value of drag obtained by ONERA is very close to the CFD median of all DPW-5 participants [30], i.e. 250 drag counts for the CRM wing-body (135 counts of pressure drag and 115 counts of friction), the confidence in these values can be considered as satisfactory.…”

Enabling the environmentally clean air transportation of the future: a vision of computational fluid dynamics in 2030

“…(ii) Physical modelling Advances in the physical modelling of turbulence for separated flows, transition and combustion are critically needed to achieve the desired state of CFD in 2030 [8,[12][13][14][15][16][17]. For the advancement of turbulent flow simulation, three separate tracks for research are proposed: RANS-based turbulence treatments; hybrid RANS/LES approaches where the entire boundary layer is resolved with RANS-based models, and the outer flow is resolved with LES models; and LES, including both wall-modelled (WMLES) and wall-resolved (WRLES).…”

Optimization by CFD analyses of riblet distribution over a transonic civil aircraft configuration

“…In this table, the drag coefficient is split in friction and pressure. The induced drag, as in the analysis of DP5W results, 30 is evaluated as C Di = C 2 L πAR , whereas the profile drag is estimated as C Dp = C D − C Di . At the same lift coefficient, the C D and also the friction and pressure components decrease of about the same order of magnitude when the riblets are applied.…”

“…This has been the subject of the 5 th AIAA CFD Drag Prediction Workshop (DP5W). 30 The medium grid (namely L3 ) of DPW5 has been used. Transonic simulations at M ∞ = 0.85 and Re ∞ = 5 × 10 6 have been performed.…”