Validation of STAR-CCM+ for External Aerodynamics in the Aerospace - PowerPoint PPT Presentation

Validation of STAR-CCM+ for External Aerodynamics in the Aerospace Industry

CD- adapco‟s Commitment To The Aerospace & Defense Industry “ CD-adapco is committed to the aerospace industry. I can assure our friends in the aerospace engineering community that we will continue to leverage our experience and expertise in order to provide solutions that have the flexibility to accurately solve this industry's broad range of flow, thermal, and stress problems with unprecedented efficiency . ” Steve MacDonald, CD-adapco President

What Do You Expect from Your CAE Software? Flexibility • » Meshing – Hex, Tet, Poly » Solvers – Segregated, Implicit/Explicit Coupled Experience • » Highly trained and experienced staff in every facet of the company Efficiency • » Leader in software development for HPC, mesh technology, etc. Accuracy • » RAE 2822 » ONERA M6 » Multi-Element Airfoil » Drag Prediction Workshop (Wing-Body) » Joint Common Missile (Lockheed Martin Missiles and Fire Control) » Missile Validation Cases (NAVAIR China Lake) » Impinging Jet & Supersonic Nozzle 3

What Do You Expect from Your CAE Software? Flexibility • » Processes – CAD-Embedded, Surface Wrapping, etc. » Meshing – Hex, Tet, Poly » Solvers – Segregated, Implicit/Explicit Coupled Experience • » Highly trained and experienced staff in every facet of the company Efficiency • » Leader in software development for HPC, mesh technology, etc. Accuracy • » Validated by 30+ years of use & development » Jointly validate by CD-adapco and by our customers 4

Accuracy For Aerospace Applications “Over the past years, we have used STAR -CCM+ to predict the aerodynamic performance of both commercial and military aircraft. In particular, we ran cases from the 2nd Drag Prediction Workshop and obtained excellent results compared with experiment.” Matt Milne, QinetiQ 28 Years of experience • Proven accuracy by industrial users • Validated and tested at every stage •

RAE 2822 Case Definition Mesh: 24,576 cells (369x65 structured C-grid) • M=0.729, a = 2.31, Re=6.5e6 • Coupled implicit solver (2 nd order) • 6

RAE 2822 Coupled Solver Convergence 7

RAE 2822 STAR-CCM+ Validation 8

RAE 2822 NASA Code Validation 9

ONERA M6 Validation case University of Czestochowa, Poland • 10

Experimental data Two cases – angle of attack 3.03 ° and 6.06 ° . Mach 0.839 Cp values on 7 sections across wing. Section A Section G 11

STAR-CCM+ vs Experiment 3 ° case - Section C For 3 ° case, excellent results for NASA mesh: • Polyhedral mesh not run. Section C – k-Epsilon – NASA hexa mesh • 12

STAR-CCM+ vs Experiment 6 ° case - Section F For „difficult‟ 6° case, NASA mesh performs well on in- • board sections but poorly on sections close to wing tip However, polyhedral mesh gives excellent results for • all sections. 13

ONERA M6 Tutorial Volume Sources + Auto Remesh + Auto Solution Mapping…. 14

High-Lift Multi-Element Airfoil STAR-CCM+ Advanced Hex Mesh (AKA Trimmed Cell) • Implicit Coupled Solver @ M~0.2, Re=5e6 • 15

High-Lift Multi-Element Airfoil 16

High-Lift Multi-Element Airfoil 17

High-Lift Multi-Element Airfoil 18

High-Lift Multi-Element Airfoil a =8.01 19

High-Lift Multi-Element Airfoil a =16.21 20

High-Lift Multi-Element Airfoil a =21.29 21

AIAA 3 rd Drag Prediction Workshop 22

Wing-Body Configuration With/Without Fairing 23

Mesh Generation: Define Volume Sources “Cone” Volume Sources for Leading Edge Refinement 24

Mesh Generation: Define Volume Sources “Cone” Volume Sources for Trailing Edge Refinement 25

Mesh Generation: Define Volume Sources “Cone” Volume Sources for Wake Refinement 26

Mesh Generation: Define Volume Sources “Cone” Volume Sources for Tip and Tail Refinement 27

Mesh Generation: Define Volume Sources “Cone” Volume Sources for Shock Capture And Fairing Refinement 28

Results 29

AIAA DPW3 Lift 30

AIAA DPW3 Drag Polar 31

STAR-CCM+: Validated for Drag Prediction Flexible and easy CAD import/integration • Flexible, powerful and easy mesh generation • Fast, accurate solutions that have been validated • Drag Prediction Workshop 3 Wing-Body Configuration 0.800 0.700 Experiment STAR-CCM+ 0.600 0.500 Cl 0.400 0.300 0.200 0.100 0.000 0.016 0.018 0.020 0.022 0.024 0.026 0.028 0.030 0.032 0.034 0.036 0.038 0.040 Cd 32

Transonic Drag Rise Validation Case The objective was validate STAR-CCM+ simulation • methodologies for a zero-lift drag rise as a known body passes through mach 1. The input surfaces and boundary conditions were • generated based on the data provided in NACA paper 1160. STAR-CCM+ preformed very well for all speeds tested. • 33

Transonic Drag Rise Validation Case The focus of this set of simulations • was to accurately capture the drag rise as the RM-10 passes through the sound barrier Speeds from Mach number 0.7-1.2 • were chosen STAR-CCM+ was used to mesh and • solve the problem Because the body is in a zero lift • configuration it was only necessary to model 90 degrees of the body 34

STAR-CCM+ Automated Hex Mesh A hex-dominant mesh was chosen to discretize the • volume Near wall cells were body fitted (prism layer) cells in 12 • layers with varying thickness depending on location The final volume mesh contained 2.1 Million Cells • 35

Data Comparison 36

LMMFC Orlando STAR-CCM+ Validation Case Joint Common Missile (JCM) • Basic lift, drag, and pitching moment performance – Evaluated against wind tunnel data – Mach: 0.50, 0.75, 1.25 » » Alpha: 0 – 20 degrees Beta / Phi: 0 » Study done jointly by LMMFC and CD-adapco • (Thanks to Glenn Gebert and Deryl Snyder at LMMFC) 37

Grid / Computational Domain CAD geometry imported in IGES • format Surface wrapper / remesher used to » clean up geometry Complex protrusions, straps, » mounts, holes, etc. Polyhedral volume mesh • Volume sources used to refine mesh » in critical areas 5 rows of prism layers near the walls » Wall y + ~ 30 – 90 » Approximately 3 million cells overall » Boundary conditions • No- slip walls with „All y+ Wall » Treatment‟ boundary conditions at the walls Freestream conditions applied 250 » diameters away from missile 38

Lift Coefficient 5 Mach 0.50 StarCCM+ Mach 0.50 SplitFlow Mach 0.50 Tunnel 4 Mach 0.75 StarCCM+ Mach 0.75 SplitFlow Mach 0.75 Tunnel 3 Mach 1.25 StarCCM+ Mach 1.25 SplitFlow Mach 1.25 Tunnel C L 2 1 0 -1 -5 0 5 10 15 20 25 Alpha (deg) 39

Drag Coefficient 3 Mach 0.50 StarCCM+ Mach 0.50 SplitFlow Mach 0.50 Tunnel 2.5 Mach 0.75 StarCCM+ Mach 0.75 SplitFlow Mach 0.75 Tunnel 2 Mach 1.25 StarCCM+ Mach 1.25 SplitFlow Mach 1.25 Tunnel C D 1.5 1 0.5 0 -5 0 5 10 15 20 25 Alpha (deg) 40

Lift to Drag Ratio 4 Mach 0.50 StarCCM+ Mach 0.50 SplitFlow 3.5 Mach 0.50 Tunnel Mach 0.75 StarCCM+ 3 Mach 0.75 SplitFlow Mach 0.75 Tunnel 2.5 Mach 1.25 StarCCM+ Mach 1.25 SplitFlow 2 Mach 1.25 Tunnel L/D 1.5 1 0.5 0 -0.5 -1 -5 0 5 10 15 20 25 Alpha (deg) 41

Pitching Moment 1 0 -1 C m Mach 0.50 StarCCM+ Mach 0.50 SplitFlow Mach 0.50 Tunnel -2 Mach 0.75 StarCCM+ Mach 0.75 SplitFlow Mach 0.75 Tunnel -3 Mach 1.25 StarCCM+ Mach 1.25 SplitFlow Mach 1.25 Tunnel -4 -5 0 5 10 15 20 25 Alpha (deg) 42

LMMFC Conclusions Results • – STAR-CCM+ predicted lift forces comparable to that of Splitflow: generally within 5% » Under-predicted at low Mach numbers – STAR-CCM+ predicted drag forces significantly better than Splitflow: generally within 5% (within 1.5% @ Mach 1.25) – STAR-CCM+ predicted pitching moments significantly better than Splitflow: trim angle generally within 1 degree General Comments from LMMFC • – STAR-CCM+ is now the standard tool for refined analyses, drag-critical, internal/external flows, conjugate heat transfer, etc. 43

NAVAIR China Lake Validation Studies Missile external aerodynamics • Two public domain cases • Independent validation (no involvement from CD- • adapco) Data and statements supplied directly by Ron Shultz • and Peter Cross from NAVAIR China Lake (US Navy) 44

STAR-CCM+ RUN METRICS TANDEM CONTROL MISSILE IN “PLUS” CONFIGURATION • HALF MODEL – APPROXIMATELY 1.5M CELLS – MESHING TIME – <5 MINUTES SURFACE MESH » ~30 MINUTES VOLUME MESH » SOLUTION TIME – ~3 HOURS PER ALPHA (~600-700 ITERATIONS) » FULL ALPHA SWEEP IN <48 HOURS » TANDEM CONTROL MISSILE IN “CROSS” CONFIGURATION • HALF MODEL – APPROXIMATELY 2.0M CELLS – MESHING TIME – <5 MINUTES SURFACE MESH » ~50 MINUTES VOLUME MESH » SOLUTION TIME – ~6 HOURS PER ALPHA (~1200 ITERATIONS) » FULL ALPHA SWEEP IN <72 HOURS » 45

TANDEM CONTROL “ + ” CONFIGURATION Axial Force - "Plus" Configuration 1.80 1.60 1.40 Run 47 1.20 Run 1003 Axial Force Coefficient Star-CCM+ 0/0 Run 1015 1.00 Star-CCM+ 0/-20 Run 1010 Star-CCM+ 20/0 0.80 Run 1046 Star-CCM+ 20/-20 0.60 Run 53 Star-CCM+ 10/10 0.40 0.20 0.00 -5 0 5 10 15 20 25 30 Angle of Attack, degrees 46