HLPW6: Reynolds-Averaged Navier-Stokes (RANS) Technical Focus Group (TFG)

Welcome to the RANS TFG page for AIAA High Lift Prediction Workshop 6 (HLPW6). This group explores RANS solutions for high-lift configurations, focusing on accuracy, iterative and grid convergence, and turbulence modeling for industrial applications. The specific goal of the HLPW6 RANS TFG is to understand and mitigate spurious separation patterns often observed behind slat brackets in RANS solutions for high-lift configurations at high angles of attack. We are mainly focusing on RANS solutions for Test Case 1 (TC1) configuration, but plan to apply the lessons learned during this study to improve RANS solutions for Test Case 2 (TC2) configurations. See links to the geometry description and organizing committee provided grids below.

Join the TFG Distribution List

• Email: boris.diskin@nasa.gov or mike@flexcompute.com

Meeting Schedule and Access

• Bi-weekly on Wednesday at 10:00 am EDT (EST between November 1, 2026 and March 13, 2027) Meeting link (Teams)
  • Subgroup Visualization and Characterization of Bracket Wakes. Next meeting Thursday March 26, 7 pm EDT Meeting link.
  • Subgroups Iterative and Grid-convergence Criteria, and Verification of SST-Vm Model. Next meeting April 3, 10 am EDT Meeting Link.

Group Leadership

• Boris Diskin— NASA’s Langley Research Center
• Michael Park — Flexcompute Inc.

Test Cases

• Link to website page: https://aiaa-hlpw.org/HLPW6/cases
• Test Case 1 — CRM-HLS (Simplified High-Lift Common Research Model)
• Test Case 2 — ONERA LRM 2.3 or 2.4 (the HLPW-5 configurations)
• Test Case 3 (Optional) — CRM-HL Take-off Configuration
• SST-Vm Verification Case: model and test case descriptions

Schedule and Milestones

• Mini-Workshop 1: AIAA Aviation 2026 (8–12 June, San Diego, CA)
  Session time: 5:30 pm PDT, Room Harbor B (hybrid option planned)
  • Preliminary RANS solutions for TC1
  • Comparison with TC1 SRS
  • Preliminary summary of RANS TC1 solutions
• Mini-Workshop 2: AIAA SciTech 2027 (11–15 Jan, Orlando, FL)
  • Updated RANS solutions for TC
  • Comparison with experiment
  • Geometric variations of TC1, first application of lessons learned to TC2
  • RANS model modifications
  • Midterm summary of RANS TC1 and TC2 solutions
• HLPW-6: AIAA Aviation 2027 (7–11 June, San Diego, CA)
  • Final RANS solutions for TC1
  • RANS solutions for TC2 (Config. 2.4) single Re, limited angles of attack
  • Final RANS TFG report
• AIAA SciTech 2028 (10–14 Jan, Orlando, FL): HLPW-6 special sessions

Meeting Format

• Leadership updates (short)
• Participant updates (majority of time) — verbal and prepared updates welcome
• Open discussion

Key Questions

General

1. Can we compute iteratively and grid converged RANS solutions for TC1?
2. Can we achieve agreement between converged RANS solutions computed by different solvers for TC1 at low, middle, and high angles of attack?
3. Is TC1 geometry prone to spurious ‘pizza slice’ separation patterns similar to those observed in RANS solutions at high angles of attack for TC2?
4. Can spurious ‘pizza slice’ separation patterns be mitigated with better grid resolution and/or iterative convergence? If yes, what are requirements for grid resolution (both on surface and in volume) and levels of convergence to avoid spurious separation?
5. Do we observe multiple solutions of the Spalart-Allmaras (SA) turbulence model for TC1 and, if we do, what changes in the turbulence model should be made to ensure well-posedness (solution existence, uniqueness, and continuous dependence on the input parameters)?
6. What lessons learned from TC1 can be applicable to more complex CRM-HL configurations such as TC 2.4?

Optional

• How do geometrical features (bracket shape / spacing between brackets, anything else) affect spurious separation in the RANS solutions?

Resources and Support

• Tecplot complimentary licenses available for workshop participants
  Contact: Gibson Adams — g.adams@tecplot.com
• RANS grids are available — https://aiaa-hlpw.org/HLPW6/grids

Presentations from Bi-Weekly TFG Meetings

• TFG Meeting 3/25/26 Presentation 01
• TFG Meeting 2/25/26 Presentations 01 02
• TFG Meeting 2/11/26 Presentations 01 02
• Kickoff Meeting: 1/28/26

HLPW6 Website

• Main site: https://aiaa-hlpw.org/
• Cases page: https://aiaa-hlpw.org/HLPW6/cases
• This TFG page: https://aiaa-hlpw.org/HLPW6/TFG_RANS

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Last updated: 2026-03-02