18b3524992ffc048cf16a892d18f5495.ppt

- Количество слайдов: 50

ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Benchmarking CEASIOM Software to Predict Flight Control and Flying Qualities of the B-747 A. Da Ronch The University of Liverpool, UK C. Mc. Farlane, C. Beaverstock Bristol University, UK J. Oppelstrup, M. Zhang, A. Rizzi Royal Institute of Technology, Sweden ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Introduction • Contemporary aircraft conceptual design o Handbook methods, semi-empirical theory o Need to recalibrate these empirical methods • Augmented-stability & extended flight envelope o More accurate flight dynamics modelling o Computational methods based on first principle o First-Time-Right with the FCS design architecture ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

CEASIOM Computerized Environment for Aircraft Synthesis and Integrated Optimization Methods o Sim. SAC project under the European Commission 6 th Framework Programme o Integrates discipline-specific tools for conceptual design to predict flying & handling qualities http: /www. simsacdesign. eu http: /www. ceasiom. com ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Objectives ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

CEASIOM main GUI ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Test Case: Boeing 747 • Large 4 -engined turbofan; 350+ pax • Multiple control surfaces: Krueger LE flaps, triple-slotted TE flaps • Flight dynamics with FCSDT to evaluate different fidelity-level approx ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Adaptive Fidelity CFD 1. DATCOM o Semi-empirical 2. TORNADO o Vortex-Lattice method 3. EDGE o CFD solver Fidelity ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk CPU Time Geometry

Adaptive Fidelity CFD 1. DATCOM o Semi-empirical 2. TORNADO o Vortex-Lattice method 3. EDGE o CFD solver ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk • For conventional aircraft, estimate aero derivatives based on geometry details and flight conditions • Suspect results for new configuration • Handbook

Adaptive Fidelity CFD 1. DATCOM o Semi-empirical 2. TORNADO o Vortex-Lattice method 3. EDGE o CFD solver • Modified horse-shoe vortex singularity method • Steady & low reduced-freq harmonic unsteady flows • Prandtl-Glauert similarity role for compressibility • Fuselage can be modelled http: /www. redhammer. se/tornado/ ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Adaptive Fidelity CFD 1. DATCOM o Semi-empirical 2. TORNADO • 3 D NS/Euler, compressible flow solver from FOI, Sweden • Unstructured grids with arbitrary elements; node-centred FV Vortex-Lattice method • Explicit Runge-Kutta integration to steady state 3. EDGE • Semi-implicit, dual-time method o CFD solver for unsteady problem o ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk • Acceleration techniques, turbulence models, parallel implementation

CFD Code - EDGE Deflection of control surfaces 1. Generation of a new grid for every new configuration of deflected control surfaces clean geometry tens of grids needed 2. Transpiration BCs only one single grid needed limits on min/max deflection ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Challenges 1. How to automate grid generation for CFD? 2. How to do 100 k CFD? 3. How to do S&C analysis early in design phase? “. . . whether CFD can participate in the design process with sufficient speed to drive down the design cycle time”, Dawes et al. ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Challenges 1. How to automate grid generation for CFD? 2. How to do 100 k CFD? 3. How to do S&C analysis early in design phase? ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

From Geometry to CFD Grid (1) Ac. Builder: sketch-pad - Edit XML file to match new design - Visual interpretation ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

From Geometry to CFD Grid (2) SUMO* (SUrface MOdeler) • Rapid generation of 3 D water-tight geometry • Automated generation of unstructured surface mesh • Triangulation based on in-sphere criterion, better than Delaunay, for skewed surfaces • Volume mesh using Tet. Gen ICAS Paper no. 282 * http: /www. larosterna. com/dwfs. html Nice, September 2010 A. [email protected] ac. uk

From Geometry to CFD Grid (2) SUMO surface grid ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

From Geometry to CFD Grid (2) SUMO volume grid ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

From Geometry to CFD Grid ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

TORNADO Geometry ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

TORNADO Geometry Munk’s theory Sink/source distribution ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

TORNADO Geometry ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Challenges 1. How to automate grid generation for CFD? 2. How to do 100 k CFD? 3. How to do S&C analysis early in design phase? ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Aerodynamic Table Format Flight Variables Ao. A Mach Beta Elev Rud Ail. . . Coefficients p q r CL CD Cm CY Cl Cn - - - - - - - - - - - ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk - - - Non-conventional controls

Brute Force Approach • Simple example; let’s assume: o 10 values for Ao. A, Mach, Beta, Elev, Rud, Ail o More than 100 k entries needed in table o 10 seconds each calculation using TORNADO ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Brute Force Approach • Simple example; let’s assume: o 10 values for Ao. A, Mach, Beta, Elev, Rud, Ail o More than 100 k entries needed in table o 10 seconds each calculation using TORNADO 106 / (24 * 60) > 10 days Brute force approach not feasible to fill-in aero tables! ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Sampling & Data Fusion Flight Dynamics Database Existing Table Increments to Design Data Fusion for Aerodynamic Increments Aerodynamic Tables Kriging Sampling ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk New Design Journal of Aircraft, 46 (3), 2009

Sampling & Data Fusion • STATIC effects: o Sampling for M-α-β dependence o Co-Kriging to calculate increments (controls) • DYNAMIC effects: o No frequency dependence o Alpha dependence only o Replace unsteady time-accurate with HB method? * o Stability derivatives from DATCOM ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk * AIAA Journal, 47 (4), 2009

Challenges 1. How to automate grid generation for CFD? 2. How to do 100 k CFD? 3. How to do S&C analysis early in design phase? ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

FCSDT (Flight Control System Design Toolkit) • Design of the FCS, FCS architecture design • Reliability analysis, failure mode analysis • Control allocation, response simulation • S&C analysis, HQ assessment, control laws design, control laws definition, flight simulation ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Aerodynamic Predictions 1. Low speed aerodynamics 2. Transonic regime • DATCOM • TORNADO with compressibility correction • EDGE in Euler mode More comparisons in the paper; exp data from ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk Rodney, C. H. , Nordwall, D. R. , 1970

CL vs α, Mach = 0. 80 ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

CD vs CL, Mach = 0. 80 ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Cm vs α, Mach = 0. 80 ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Mach = 0. 80 Ao. A = 1. 0 deg Positive elev deflection ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Results 1. Cruise condition • Trim & Stability analysis • Eigen-structure assignment for feedback controller A + B *K • Flight Handling Qualities 2. Failed lower rudder segment • Trim & Stability analysis ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Trimmed Ao. A ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Trimmed elevator ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Pole plot, Mach = 0. 8 Short Period Dutch-Roll Phugoid ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Results 1. Cruise condition Eigen value: -2 ± i *2 for Short Period mode • Trim & Stability analysis • Eigen-structure assignment for feedback controller A + B *K • Flight Handling Qualities 2. Failed lower rudder segment • Trim & Stability analysis ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Kα: gain value of feedback Ao. A to elevator Kq: gain value of feedback pitch rate to elevator ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Results 1. Cruise condition • Trim & Stability analysis • Eigen-structure assignment for feedback controller A + B *K • Flight Handling Qualities 2. Failed lower rudder segment • Trim & Stability analysis ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Short Period mode ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk Eigenvalue: ƞ + i *ω T 1/2 = ln(2) / |ƞ|

Phugoid mode ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk ξ: damping ratio ωn: undamped circular freq

Dutch Roll mode ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk ξ: damping ratio ωn: undamped circular freq

Results 1. Cruise condition Lower rudder segment failed at -10 o for range of Mach numbers • Trim & Stability analysis • Eigen-structure assignment for feedback controller A + B *K • Flight Handling Qualities 2. Failed lower rudder segment • Trim & Stability analysis ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Conclusions • Aero tables for flight mechanics o Automated generation of CFD grid o From low-fidelity methods to CFD o Multiple control surfaces o Smart procedure to fuse data • Test case: Boeing 747, trim analysis & poles plot o Cruise condition o Failure analysis: lower rudder segment jammed • Demonstrated o Robust process for S&C analysis in early design o CFD needed for good prediction for a realistic test case ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk

Future Works • Flight manoeuvre replay o Aero table with dynamic derivatives from HB o Replay with CFD o When does prediction fail? * Unsteady effects? • Need to review model for flight mechanics o System ID o Indicial (successfully used in gust analyses) o State Space • Towards modelling of unsteady effects ICAS Paper no. 282 Nice, September 2010 A. [email protected] ac. uk * AIAA-2009 -6273