Formula 1 Aerodynamic Assessment by Means of CFD Modelling

Transcription

1 Formula 1 Aerodynamic Assessment by Means of CFD Modelling DANSIS Automotive Fluid Dynamics Seminar 25 March 2015 Copenhagen Denmark Dr. Lesmana Djayapertapa Senior CFD Consultant LR Senergy Aberdeen - UK

2 Agenda Wind Tunnel (WT) Testing and CFD in Formula 1 Aeroelasticity Analysis Rear Wing Aerodynamic Design CFD-Based Virtual Optimisation Approach Summary

3 CFD Usage (TFLOPS) Wind Tunnel (WT) Testing & CFD WT is still the main aerodynamic design tool 50% model scale Running 24 hours a day, 7 days a week CFD compliments WT Testing, filters aerodynamic design ideas, possibly steer wind tunnel testing programme F1 teams usually have their own High Performance Computing centre WT wind on weekly testing hours and CFD Usage were (used to be) recorded, and need to be on or below the purple line FOTA Aerodynamic Restriction FOTA Aero Limit WT Hours

4 CFD Usage (Some Examples...) Rear Wing Aerodynamic Design CFD-based Optimisation Nose & Front Wing Pillar Aerodynamic Design Front Wing Aerodynamic Design Front Floor Diffuser Interaction Front Suspension Aerodynamic Design

5 Aeroelasticity Analysis CAD CFD Model FEA Model Mesh Deformation Displacement Converged? CFD Pressure interpolated from CFD to FEA mesh FEA Displacement (Deformation) Benefits of Aeroelasticity: Increased (Front) Down Force Drag Reduction Better Control of Aerodynamic Balance Final Shape Aerodynamic Balance / Centre Of Pressure / Front Balance Czt FCP AB RCP Czf Wheel base Czr

6 At 300km/h the airflow past the Front Wing can generate approximately 250kg of down-force per side: FRONT WING AERODYNAMIC LOAD The carbon fibre structure tends to bend under this loading: 300km/h 300km/h

7 FW DEFLECTION Stress analysis (FEA) of the composite structure is used to estimate to amount of deflection under the aerodynamic load: Comparison between design FW position and deflected geometry

8 DEFLECTED FW LOAD When the FW defects its loading increases (ground effect)... Increased in FW load Need to maintain coherent FW vortices...this also has downstream effect benefits Total car downforce increase can be even more significant

9 CFD-Based Aerodynamic Design Optimisation

10 Typical Design Optimisation Flow Chart Initial Design Background Effort Final Design Optimiser Parametric Base Geometry CAD Geometry Rule Bases Results Extraction Search CFD Meshing CSM Boundary Conditions Post Processing CFD + Mesh Deformation + Optimisation

11 Aim: to further explore the design space, looking for possible design to achieve certain objectives Due to CPU-intensive analysis: Design of Experiment (DoE) Response Surface Model (RSM) Virtual Optimisation

12 DOE-RSM-(Virtual) Optimisation Cluster Parallel Analysis Initial Geometry DoE CFD CFD CFD CFD CFD CFD CFD CFD CFD CFD CFD CFD Build the Initial Training Database Construct RSM Evaluate RSM Virtual Optimisation Using RSM CFD CFD CFD RSM Tuning Validate the virtual points, and enrich the Training Data base Adequate? Best Design

13 The Geometry Isolated Rear Wing (RW) RW is not mounted to the race car Inlet flow conditions are obtained from full car run to provide realistic flow condition

14 Czrw Rear Wing Down force The Design Objective To maximise perpendicular distance from the RW polar line Medium Down force family 78 UPD9_ISOLA_RW UPD9_ISOLA_RW; 15mm Slot Gap High Down force family Distance d BSL Low Down force family 73 +2DEG 72 y = x RW R² = Polar 1 +4DEG Rear Wing Drag Cxrw

15 The Design Parameters Nose height slot gap normal position Slot gap streamwise position 3 parameters per section 3 sections along the span Total 9 design parameters

16 Volume Mesh Deformation Auto Checks for: Mesh Validity; and Mesh Quality

17 Maximum Distance The Max Distance Convergence 1 st Loop 2 nd Loop 3 rd Loop DOE Points Baseline Optimisation Loop

18 Czrw DOE Points Baseline Cxrw

19 Czrw 1 st Optimisation Loop Baseline Cxrw

20 Czrw 2 nd Optimisation Loop Baseline Cxrw

21 Rear Wing Down force 3 rd Optimisation Loop Medium Down force (Max Efficiency) family High Down force family Baseline Low Down force family Rear Wing Drag

22 Delta Aero Coeff (Points) The Accuracy of the Virtual Design 0.1 Delta Cxrw & Czrw (Virtual Design - Real Design) Delta Czrw (pts) Delta Cxrw Design ID

23 Rear Wing Shape Changes Baseline

24 Summary Wind Tunnel Testing and CFD in Formula 1 Front Wing Deflection Analysis using CFD-Structural Coupling Further Exploring Rear Wing Design Space using CFD- Based Virtual Aerodynamic Optimisation

25 Thank You

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