Fluid Dynamics Challenges in Flight Mechanics WG

1. Fluid Dynamics Challenges in Flight Mechanics WG For AIAA FD/APA TC Joint Working Group meeting San Antonio, June 21st, 2009

2. Topics • Objective and Approach • After the White Paper – formation of Working Group • Outline JWG plan • San Antonio 2009 Invited Session • Interesting Topics by Speakers from Industry and Government • Orlando 2010 focal topics • Transonic SWBLI • Smooth-surface separation • Working up workshop definitions/protocols • Work to be done by JWG before Orlando 2010

3. Fluid Dynamics Challenges in Flight Mechanics Objective • Identify (and try to close) gaps in flight mechanics (pitch-up, buffet, wing-drop, etc.) CFD prediction capability based on relevant fluid dynamic phenomena - Relate flight mechanics issues to fluid mechanics responsible for handling issues (e.g., transition, shock/boundary-layer interaction, separation, unsteadiness, etc.) - Not focused on a single vehicle geometry Approach • Produce White Paper to identify specific flow phenomena which have problematic consequences for the flying qualities of aircraft • Develop Workshop(s) (with specific geometries) to evaluate CFD predictions and define needs for additional experimental data where necessary • Joint effort between APA and other TC’s (FD, AFM, and Flight Test) as well as Academia. Plan to coordinate with RTO on fundamental issues

4. After the White Paper – formation of Working Group • White Paper developed by APA sub-TC (Vehicle Aerodynamics) • “Taxonomy of Flight Mechanics Issues for Aircraft, and underlying Fluid-Dynamics Phenomena”, AIAA-2009-0744. Presented at Orlando 2009 • Well-received by stakeholders • Industry representatives on APA/FD TCs • Government representatives and budget holders (AFRL/NASA) • AIAA Public Policy team – suggest development into a position paper • Working group inaugurated at Orlando • Members from AFM, APA and FD TCs • Need to ensure balanced team • Additional members co-opted as necessary • Required knowledge base/skill set will evolve through the life of the working group • Approximately fortnightly conference call to progress agenda

5. Current Working Group Membership (May 2009) • AFM TC • Ashok Gopalarathnam (NCSU) • APA TC • Eric Charlton (Lockheed Martin)* • Stephen McParlin (QinetiQ) • Robert Tramel (Kord technologies) • Paul Vijgen (Boeing)* • FD TC • Mark Glauser (Syracuse University) • Michael Ol (AFRL) • Carl Tilmann (AFRL)* • Others • Mike Fremaux (NASA) • Charles Hirsch (Ercoftac) • Rich Wahls (NASA) *rotated off TC, still on WG

6. Outline plan for Working Group (1) • Working Groups are expected to have a three-year life and a clear set of deliverables. • In year 1: • Publication of White Paper (Orlando 2009) • First invited session to expound issues (San Antonio 2009) • In year 2: • Focus on specific flow phenomena • Transonic SWBLI • Smooth-surface separations • Invited sessions covering experimental knowledge base for focus areas (Orlando 2010) • Definition of experimental basis for workshops (Chicago 2010) • Session on modeling of causative flow phenomena in CFD?

7. Outline plan for Working Group (2) • In year 3: • Publish statement on postulated causative flow physics for use by workshop participants (by Orlando 2011) • Release test case geometry and flow conditions (Orlando 2011) • Have halfway workshop session(s) in Hawaii 2011 • Final workshop and results targeted ASM 2012 • Effort needed: • Definition of experimental data sets (need FD lead) • Agree methodology for comparing CFD results • Agree how to test incremental effect of new physics in CFD • JWG can benefit from logistic experiences of Drag Workshops

8. San Antonio 2009 Invited Session • Thursday morning June 25, 08:00-11:30, have excellent speakers and topics: • Atlee Cunningham, LM Fort Worth, “Real-life adventures with unsteady aerodynamics” • Jerry Jenkins, AFRL, “Nonlinear and time-dependent aerodynamic characteristics: Implications for testing and flight mechanics analysis” • Mike Fremaux, NASA Langley, “NASA COMSAC Project: Lessons Learned” • Dan Vicroy, NASA Langley, “Overview of RTO AVT-161 Assessment of Stability and Control Prediction Methods for NATO Air and Sea Vehicles” • Open discussion forum • WG to meet after session to review feedback and programme • Audience participation/buy-in sought

9. Orlando ASM 2010 – focal topics of invited sessions • Identifying/firming up on invited speakers • Transonic SWBLI • Holger Babinsky/Piotr Doerffer • TBD from Boeing Commercial on buffet • Smooth-surface separation • Murray Tobak, NASA Ames (retd.) • Jim Luckring, NASA Langley (?) • Tony Hutton, Airbus (?) • Suggestions for possible further speakers • Frank Lynch (Douglas, retired) • Joe Chambers (NASA Langley, retired) • ONERA person on buffet • Use “information triad” as a basis to categorize papers? • Suggest FD TC (Mark Glauser et al.) incorporate into the structure

10. Tasks for consideration before/at Orlando ASM 2010 (1) • We want to identify the primary causative fluids phenomena • Ensure these are modeled in CFD • Identify useful empiricisms where appropriate • How do we disseminate this information? • Where are there gaps in understanding? • Review existing experimental data sets • Where are there known discrepancies between CFD and experiment • Make case for ‘building block’ experiments as gap fillers

11. Tasks for consideration before/at Orlando ASM 2010 (2) • “Unfinished business” Public Policy aspects • Develop the White Paper into a AIAA position statement ? • Plan is to meet with Jim Keenan in San Antonio and find out whether White Paper could be the basis for AIAA position statement • (format, requirements, customer, approval chain, sign-off) • Copies of oral presentations at JWG Special Sessions • Need to agree on what to do with copies of oral presentation PPTs • Recommend to request authors/presenters that at least a copy of their PPT is allowed to be available within Joint Working group for planning and coordination. • Can we put presentations on JWG sharepoint ? What is AIAA policy ? • Further develop active participation from AFM and Flight Test TC’s

12. Possible Joint WG Publications after 2009 White Paper • White paper (AIAA-2009-0744) addressed several topics. Paper could provide basis for follow-on paper(s) developed by Joint WG members • Further develop postulated causative flow physics for specific relevant flight mechanical topics • Examples of practical issues (“case studies”) • Summary (by WG members) of oral papers presented in San Antonio and Orlando Special Sessions • Publication by Special Session authors • Introductions to Workshop

13. Need to Populate AIAA SharePoint for JWG activities • https://info.aiaa.org/tac/ASG/APATC/default.aspx • Recommend (restricted-access) folder for JWG members • Can we use this Sharepoint in 2010+ for workshop test cases ? • Jim Guglielmo has suggested a distinct WG site on the AIAA server. He can set up a site, but we need to decide how to run it. Any volunteers?

14. Need to identify focal points within JWG • Maintain Sharepoint site. • Public policy version of White Paper. • Session chair to organise process for Transonic SWBLI. • Session chair to organise Smooth Surface Separation. • I can do this one. Need volunteers for others [SMcP] • Liaise with NASA on RTO and relevant special publications. • Start defining possible cases for workshops. • Recruitment from new TC members (esp. FD)

16. Manoeuvre limits for combat aircraft