Statistical Analysis of CFD Solutions from the Fourth AIAA Drag Prediction Workshop

Morrison, Joseph H.

doi:10.2514/6.2010-4673

Cited by 38 publications

(32 citation statements)

References 26 publications

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“…6,7 As with previous DPW workshop, the DPW-IV test cases will in all likelihood become standard CFD test cases. Eliasson and Peng have already published a paper looking at the influence of turbulence modeling and grid resolution in computations of the CRM.…”

Section: Introductionmentioning

confidence: 99%

Application of the FUN3D Unstructured-Grid Navier-Stokes Solver to the 4th AIAA Drag Prediction Workshop Cases

Lee-Rausch

Hammond

Nielsen

et al. 2010

28th AIAA Applied Aerodynamics Conference

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FUN3D Navier-Stokes solutions were computed for the 4th AIAA Drag Prediction Workshop grid convergence study, downwash study, and Reynolds number study on a set of node-based mixed-element grids. All of the baseline tetrahedral grids were generated with the VGRID (developmental) advancing-layer and advancing-front grid generation software package following the gridding guidelines developed for the workshop. With maximum grid sizes exceeding 100 million nodes, the grid convergence study was particularly challenging for the node-based unstructured grid generators and flow solvers. At the time of the workshop, the super-fine grid with 105 million nodes and 600 million elements was the largest grid known to have been generated using VGRID. FUN3D Version 11.0 has a completely new pre-and post-processing paradigm that has been incorporated directly into the solver and functions entirely in a parallel, distributed memory environment. This feature allowed for practical pre-processing and solution times on the largest unstructured-grid size requested for the workshop. For the constant-lift grid convergence case, the convergence of total drag is approximately second-order on the finest three grids. The variation in total drag between the finest two grids is only 2 counts. At the finest grid levels, only small variations in wing and tail pressure distributions are seen with grid refinement. Similarly, a small wing side-of-body separation also shows little variation at the finest grid levels. Overall, the FUN3D results compare well with the structured-grid code CFL3D. The FUN3D downwash study and Reynolds number study results compare well with the range of results shown in the workshop presentations.

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Section: Introductionmentioning

confidence: 99%

Application of the FUN3D Unstructured-Grid Navier-Stokes Solver to the 4th AIAA Drag Prediction Workshop Cases

Lee-Rausch

Hammond

Nielsen

et al. 2010

28th AIAA Applied Aerodynamics Conference

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show abstract

“…While this improvement is quite significant, the confidence level is not down to a low enough level to compete with experimental methods. Documentation for these results can be found in summary papers [43][44] and in individual contributing papers [45][46][47][48][49][50][51][52][53][54][55][56][57][58] from two special sessions held at the 28 th Applied Aerodynamics Conference in June 2010.…”

Section: Introductionmentioning

confidence: 99%

Summary of Data from the Fifth AIAA CFD Drag Prediction Workshop

Levy¹,

Laflin²,

Tinoco

et al. 2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

103

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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.

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“…The results of DPW-V are compared to the results of DPW-II, 4 DPW-III, 6 and DPW-IV 8 for the cases that were run at constant lift. Morrison and Hemsch 6 showed that the variation in lift affected the comparisons of drag quantities and pitching moment and showed that quantities that corrected to a constant lift condition, e.g.…”

Section: B Comparison Of Dpw-v Results With Dpw-ii Dpw-iii and Dpw-ivmentioning

confidence: 99%

“…The code-to-code statistical analysis of DPW-IV identified five major findings: 8 (1) roughly 12.5% of the solutions for the Case 1 grid convergence study were outliers, (2) the code-to-code scatter for the total drag, normalized by the total drag to account for different drag levels between cases, was virtually the same for DPW-II, DPW-III, and DPW-IV, (3) the code-to-code variation of the forces and pitching moment, normalized by the appropriate force or pitching moment, was substantially larger on the horizontal tail component than on the wing or fuselage component, (4) the code-to-code variation was still substantially higher than desired by airframe designers, and (5) the drag (total drag, pressure drag, and skin friction drag) showed some reduction in scatter with increasing grid resolution.…”

mentioning

confidence: 99%

Statistical Analysis of CFD Solutions from the Fifth AIAA Drag Prediction Workshop

Morrison

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Statistical Analysis of CFD Solutions from the Fourth AIAA Drag Prediction Workshop

Cited by 38 publications

References 26 publications

Application of the FUN3D Unstructured-Grid Navier-Stokes Solver to the 4th AIAA Drag Prediction Workshop Cases

Application of the FUN3D Unstructured-Grid Navier-Stokes Solver to the 4th AIAA Drag Prediction Workshop Cases

Summary of Data from the Fifth AIAA CFD Drag Prediction Workshop

Statistical Analysis of CFD Solutions from the Fifth AIAA Drag Prediction Workshop

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