6th AIAA CFD Drag Prediction Workshop

Sponsored by the Applied Aerodynamics TC

2-Day Workshop during the AIAA AVIATION 2016 Conference

Washington, D.C. USA
16-17 June 2016

The workshop was held on Thursday and Friday during the AIAA AVIATION 2016 Conference
as an experiment in the new Forum model

Objectives

• To build on the success of past AIAA Drag Prediction Workshops.
• To assess the state-of-the-art computational methods as practical aerodynamic tools for aircraft force and moment prediction of industry relevant geometries.
• To provide an impartial forum for evaluating the effectiveness of existing computer codes and modeling techniques using Navier-Stokes solvers.
• To identify areas needing additional research and development.
  

Focus

• The focus of this workshop will be the NASA Common Research Model (CRM) with wind-tunnel measured wing twist; both wing-body and wing-body-nacelle-pylon configurations will be considered. CFD predictions of absolute and incremental force and moment values will be examined and compared. The workshop will include grid convergence and code verification studies. Additionally, an angle-of-attack sweep with static aero-elastic deformations will be considered. Grids will be made available for all required cases.
• Optionally, participants are invited to perform solution-adaption calculations and/or a coupled aero-structural simulation of the CRM wing-body configuration. A finite element model will be made available to participants to calculate twist/deflection die to aerodynamic load.

General Information

• This workshop is open to participants worldwide. Efforts will be made to ensure representation from all areas of industry, academia and government laboratories.
• Participation in the drag studies is not required to attend the workshop. Everyone is welcome!
• Open forums will be included in the workshop to discuss the solutions and modeling techniques.
• Results will be made available after the workshop in a report and on the DPW website.
• No separate registration fee will be required for attendance.
• AIAA membership is not required.

Notification of Updates

Organizing Committee

Test Cases

1. Verification Study: 2D NACA0012 Airfoil from the Turbulence Modeling Resource (TMR) sponsored by the AIAA Fluid Dynamics Technical Committee Turbulence Model Benchmarking Working Group (TMBWG). Flow conditions are: M = 0.15; Re = 6 million; angle-of-attack = 10 degrees; Reference temperature = 100°F; Farfield boundary condition at 500 chords. Solution converged on either adapted or fixed sequence grid family.

   For this verification study you are asked to run the same turbulence model(s) that you are running for the CRM cases AS WELL AS the Spalart-Allmaras (SA) model (if possible). For SA, you can compare with the NACA0012 results on the TMR website. For your other model results, they will indicate the 2D grid convergence behavior for your turbulence model, and will form the basis for future comparisons against other codes with the same model.

   For more information on this case, see the TMBWG website at: http://turbmodels.larc.nasa.gov/naca0012numerics_val_sa_withoutpv.html. If using the provided grid sequence (available at http://turbmodels.larc.nasa.gov/naca0012numerics_grids.html ), then Grid Family II should be used.

   When using the Spalart-Allmaras (SA) turbulence model, the results from 3 codes (FUN3D, CFL3D, and TAU) appear to be approaching infinitely-refined results bounded by:

   • CL = 1.0909 - 1.0911
   • CD = 0.012270 - 0.012275
   • CDp = 0.006060 - 0.006070
   • CDv = 0.006205 - 0.006206
   • Cm = 0.00676 - 0.00680

2. CRM Nacelle-Pylon Drag Increment: Calculate the drag increment between the CRM wing-body-nacelle-pylon (WBNP) and the CRM wing-body (WB) configurations. Flow conditions are: M = 0.85; Re = 5 million; fixed CL = 0.5 +/- 0.0001; Reference temperature = 100°F; aeroelastic deflections at the angle-of-attack 2.75 degrees geometry. Grid convergence study on Baseline WB and WBNP grids.
3. CRM WB Static Aero-Elastic Effect: Angle-of-attack sweeps will be conducted using the aero-elastic deflections measured in the ETW Wind Tunnel Test. Flow conditions are: M = 0.85; Re = 5 million; Reference temperature = 100°F; Angle-of-attack sweep = [2.50, 2.75, 3.00, 3.25, 3.50, 3.75, 4.00] degrees. Use the Medium Baseline grids [7 solutions on 7 grids].
4. CRM WB Grid Adaptation [Optional]: Fixed lift condition for the CRM Wing-Body using an adapted grid family provided by the participant. Flow conditions are: M = 0.85; Re = 5 million; fixed CL = 0.5 +/- 0.0001; Reference temperature = 100°F; aeroelastic deflections at the angle-of-attack 2.75 degrees geometry. Start the adaptation process from the Tiny (or Coarse) Baseline Mesh. Participants are to document the adaptation process.
5. CRM WB Coupled Aero-Structural Simulation [Optional]: Fixed lift condition for the CRM Wing-Body coupled with computational structural analysis. Flow conditions are: M = 0.85; Re = 5 million; fixed CL = 0.5 +/- 0.0001; Reference temperature = 100°F; static aeroelastic deflections calculated, starting from the undeformed geometry. Use the Medium Baseline Grid. A structural FEM will be supplied by NASA via the CRM Website. Modal shapes will also be made available.

Geometries

Update geometry files were released on 28 January 2016. Please check the notes on the Geometry link for updated information.

Grids