Schröder Summary of Flow Modulation and Fluid-Structure Interaction Findings

Results of the Collaborative Research Center SFB 401 at the RWTH Aachen University, Aachen, Germany, 1997-2008
1. Auflage 2010
ISBN: 978-3-642-04088-7
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, Band 109, 420 Seiten

Reihe: Notes on Numerical Fluid Mechanics and Multidisciplinary Design

No short description available.

Autoren/Hrsg.

Schröder, Wolfgang

Inhaltsverzeichnis

1;Title Page;2
2;Preface;6
3;Contents;8
4;List of Contributors;10
5;Introduction;14
6;Vortex Sheets of Aircraft in Takeoff and Landing;18
6.1;Introduction;19
6.2;Experimental Facilities;20
6.2.1;Wind Tunnel;20
6.2.2;Water Tunnel;20
6.2.3;Towing Tank;21
6.3;Measurement Instrumentation;22
6.3.1;Hot-Wire Anemometry;22
6.3.2;Particle Image Velocimetry;22
6.4;Model;23
6.5;Results;24
6.5.1;Near Field;24
6.5.2;Extended Near Field;28
6.5.3;Far Field;32
6.5.4;Force Fluctuations;37
6.6;Conclusion;38
6.7;References;39
7;An Adaptive Implicit Finite Volume Scheme for Compressible Turbulent Flows about Elastic Configurations;41
7.1;Introduction;41
7.2;Physical Model;43
7.2.1;Governing Equations;43
7.2.2;Turbulence Models;44
7.2.3;Transition Modeling;46
7.2.4;Boundary Conditions;48
7.3;Numerical Methods;48
7.3.1;Finite Volume Scheme;48
7.3.2;Matrix-Free Newton-Krylov Method;52
7.3.3;Fluid Structure Interaction;53
7.4;Results;53
7.4.1;Fishtail;54
7.4.2;Laminar Flat Plate;55
7.4.3;Transitional Flow over a Flat Plate;56
7.4.4;High-Lift Configuration;57
7.4.5;BAC 3-11 Airfoil - Shock Buffet;60
7.4.6;FSI - HIRENASD;60
7.4.7;Performance of the Matrix-Free Newton-Krylov Method;63
7.5;Conclusion;65
7.6;References;65
8;Timestep Control for Weakly Instationary Flows;68
8.1;Introduction;68
8.2;Governing Equations and Finite Volume Scheme;70
8.3;Adjoint Error Control - Adaptation in Time;72
8.3.1;Variational Formulation;72
8.3.2;Adjoint Error Representation for Target Functionals;73
8.3.3;Space-Time Splitting;74
8.4;The Conservative Dual Problem;75
8.5;Adaptive Concept;76
8.5.1;Asymptotic Decay Rates;77
8.6;Setup of the Numerical Experiment;78
8.7;Computational Results;81
8.7.1;Numerical Strategies;81
8.7.2;Strategy I: Fully Implicit Computational Results;83
8.7.3;Strategy II: Explicit-Implicit Computational Results;86
8.8;Conclusion;88
8.9;References;89
9;Adaptive Multiscale Methods for Flow Problems: Recent Developments;91
9.1;Introduction;91
9.2;Governing Equations and Finite Volume Schemes;93
9.3;Multiscale Analysis;94
9.4;Multiscale-Based Spatial Grid Adaptation;97
9.5;Adaptive Multiresolution Finite Volume Schemes;98
9.6;Approximate Flux and Source Approximation Strategies;101
9.7;Multilevel Time Stepping;102
9.8;FAS-Like Multilevel Scheme;103
9.9;Numerical Results;107
9.9.1;Multilevel Time Stepping: Oscillating Plate;107
9.9.2;FAS-Like Multilevel Scheme: Bump;108
9.9.3;Local Versus Exact Flux and Source Reconstruction: Burger’s Equation;110
10;Interaction of Wing-Tip Vortices and Jets in the ExtendedWake;118
10.1;Introduction;118
10.2;Governing Equations and Numerical Method;120
10.3;New One-Equation Turbulence Model;122
10.4;Adaptive Mesh Refinement;124
10.4.1;Data Communication;125
10.5;Results;128
10.5.1;RANS Simulation of the Flow over a Rectangular Wing with Engine Jets;129
10.5.2;Measurements of the Flow over a Wing with Engine Jets;131
10.5.3;Large-Eddy Simulation of Wake Vortices;135
10.6;Conclusions;144
10.7;References;145
11;Experimental and Numerical Investigation of Unsteady Transonic Airfoil Flow;149
11.1;Introduction;149
11.2;Experimental Setup;150
11.3;Numerical Method;150
11.4;Results;153
11.4.1;Wave/Shock Interactions;156
11.4.2;Variation of the Angle of Attack;158
11.4.3;Mechanisms of Pressure Wave Generation;159
11.5;References;162
12;Enabling Technologies for Robust High-Performance Simulations in Computational Fluid Dynamics;164
12.1;Introduction;164
12.2;Automatic Differentiation and Parallel Computing;165
12.2.1;Automatic Differentiation of OpenMP Programs;166
12.2.2;Automatic Scoping;167
12.3;Automatically-Generated Sensitivities in TFS;168
12.3.1;Sensitivities with Respect to Geometric Parameters;168
12.3.2;Sensitivities with Respect to Angle of Attack and Yaw Angle;175
12.4;Automatically-Generated Sensitivities in QUADFLOW;180
12.4.1;Finite Volume Scheme Implemented in QUADFLOW;180
12.4.2;Increasing the Robustness of an Approximate Newton Method;180
12.4.3;Enabling an Exact Newton Method;182
12.5;Conclusions;186
12.6;References;187
13;Influencing Aircraft Wing Vortices;192
13.1;Introduction;192
13.2;Coordinate Systems;193
13.3;Test Facilities;194
13.3.1;Wind Tunnel;194
13.3.2;Water Towing Tank at the ILR;194
13.3.3;Water Towing Tank at the DST;194
13.4;Measurement Techniques and Instrumentation;195
13.4.1;Particle Image Velocimetry;195
13.4.2;Flow Visualization;195
13.5;Results;196
13.5.1;Investigations of Wing Wakes in the Near Field with Additional Fin Vortices;196
13.5.2;Investigations of Multi-vortex Systems in the Far Field;201
13.6;Conclusion;212
14;Development of a Modular Method for Computational Aero-structural Analysis of Aircraft;216
14.1;Introduction;216
14.2;General Concept and Applied Numerical Methods;217
14.2.1;Flow Solver;219
14.2.2;Structural Solver;219
14.2.3;Flow Grid Deformation Method;220
14.2.4;The Aeroelastic Coupling Module;222
14.3;Selected Results of Preceding Funding Periods;234
14.3.1;Static and Dynamic Validation for an Elastic Swept Wing in Subsonic Flow;235
14.3.2;Static Deformation Effects in Wind Tunnel Experiments of Transport Aircraft;237
14.4;Selected Results of the Final Funding Period – Validation for the HIRENASD Experiments;239
14.4.1;Dependence of the Lift Coefficient on the Angle of Attack;240
14.4.2;Lift Divergence Behaviour;242
14.4.3;Prescribed Motion According to the Second Flap-Bending-Dominated Mode Shape;242
14.5;Conclusion;247
14.6;References;248
15;A Unified Approach to the Modeling of Airplane Wings and Numerical Grid Generation Using B-Spline Representations;250
15.1;Introduction and Overview;250
15.1.1;Parametric Grids;251
15.1.2;B-Spline Grid Generation;252
15.1.3;Generation of Wing Models;253
15.1.4;Outline of Paper;254
15.1.5;Notation;254
15.2;Geometry Description and Outline of the Modeling Process;255
15.2.1;Cross Sections and Wing Construction;255
15.2.2;Mounting Unit;257
15.2.3;The Wing Tip;259
15.2.4;Winglet Construction;260
15.3;Elliptic Grid Generation;262
15.3.1;Spekreijse’s Grid Generation System;262
15.3.2;B-Spline Collocation;262
15.3.3;Application Example;263
15.3.4;Boundary Orthogonality;264
15.3.5;Complete Boundary Control;266
15.4;Deforming Grids;268
15.4.1;Deforming the Framework;269
15.4.2;Example: High Lift Configuration;270
15.5;Conclusion;273
15.6;References;273
16;Parallel and Adaptive Methods for Fluid-Structure-Interactions;275
16.1;Introduction;276
16.2;Fluid-Structure Coupling;277
16.3;Multiscale Decompositions–Basic Ingredients;282
16.3.1;Multiscale Analysis and Grid Adaptation;283
16.3.2;Algorithms;285
16.3.3;Data Structures;287
16.4;Parallelisation;288
16.4.1;Load-Balancing via Space-Filling Curves;288
16.4.2;Parallel Grid Adaptation and Data Transfer;293
16.5;Embedding of Parallel Multiscale Library into the Quadflow Solver;295
16.6;Numerical Results;297
16.6.1;Performance Study for Multiscale Transformation;297
16.6.2;Application;300
16.7;References;303
17;Iterative Solvers for Discretized Stationary Euler Equations;305
17.1;Introduction;305
17.2;The Euler Equations;306
17.3;Test Problems;307
17.3.1;Homogeneous Stationary Flow on the Unit Square;307
17.3.2;Stationary Flow around NACA-0012 Airfoil;307
17.4;Point-Block Preconditioners;308
17.4.1;Methods;309
17.4.2;Numerical Experiments;310
17.4.3;Concluding Remarks;312
17.5;Renumbering Techniques;312
17.5.1;Methods;313
17.5.2;Numerical Experiments;317
17.5.3;Concluding Remarks;320
17.6;Time Integration;320
17.6.1;CFL Evolution Strategies;320
17.6.2;Numerical Experiments;322
17.6.3;Locally Optimal CFL Numbers;323
17.6.4;Concluding Remarks;326
17.7;Matrix-Free Methods for Second Order Jacobians;327
17.7.1;Numerical Experiments;327
17.7.2;Concluding Remarks;330
17.8;Outlook;330
17.9;References;332
18;Unsteady Transonic Fluid – Structure – Interaction at the BAC 3-11 High Aspect Ratio Swept Wing;334
18.1;Introduction;334
18.2;Experimental Setup;336
18.2.1;Wind Tunnel Facility;336
18.2.2;Swept Wing Model;337
18.2.3;Videogrammetric Model Deformation Measurement Setup;341
18.2.4;Time-Resolved Pressure-Sensitive Paint Visualization Setup;342
18.3;Steady Wing Flow Properties;344
18.3.1;Time-Averaged Flow Topology;344
18.3.2;Dynamic Shock-Boundary Layer Interaction;349
18.3.3;Wing Model Deformation;354
18.4;Forced Harmonic Wing Oscillation Experiments;355
18.4.1;Bending Degree of Freedom;356
18.4.2;Torsional Degree of Freedom;359
18.4.3;Fluid-Structure Energy Exchange;363
18.5;Conclusion;366
18.6;References;367
19;Structural Idealization of Flexible Generic Wings in Computational Aeroelasticity;371
19.1;Introduction;371
19.2;Structural Design ofWing Box;373
19.2.1;Geometry Configuration;373
19.2.2;Rib Arrangements;374
19.2.3;Stringer Arrangements;374
19.2.4;Sweep and Taper Effects;375
19.2.5;Warping Effects;375
19.2.6;Material Anisotropy;375
19.3;Structural Idealization;377
19.3.1;One-Dimensional Idealization;377
19.3.2;Three-Dimensional Idealization;379
19.3.3;Structural Dynamics;384
19.4;Numerical Results;386
19.4.1;Sweep Effects;386
19.4.2;Warping Effects;386
19.4.3;FE-Validation of Stress;388
19.4.4;Modal Analysis;388
19.4.5;Static Tailoring;391
19.4.6;Vibration Tailoring;391
19.5;Conclusions;393
19.6;References;394
20;Aero-structural Dynamics Experiments at High Reynolds Numbers;396
20.1;Introduction;397
20.2;Experimental Setup andWindtunnel Conditions;398
20.2.1;Wind Tunnel Model in the European Transonic Windtunnel;398
20.2.2;Measuring Equipment of the Wing Model;400
20.2.3;Internal Forced Vibration Excitation;403
20.2.4;Wind Tunnel Conditions;404
20.3;Selected Experimental Results from Static Tests;405
20.4;Wave Processes during the Tests for Steady Polars;410
20.4.1;Upstream Travelling Waves;410
20.5;Stochastic Processes during the Tests;414
20.5.1;Frequency and Damping Analysis;414
20.5.2;Analysis of Normal Force Caused by Stochastic Aerodynamic Disturbances;415
20.6;Selected Experimental Results from Dynamic Tests;417
20.6.1;Processing of Measured Data as for Dynamic Tests;417
20.6.2;Unsteady Polars with Defined Vibration Excitation;419
20.6.3;Influence of Parameters in Dynamic Tests on Chord-Wise Pressure Distribution;424
20.7;Conclusions;428
20.8;References;429
21;Author Index;432

Leseproben

"Development of a Modular Method for Computational Aero-structural Analysis of Aircraft (S. 205-206)

Lars Reimer, Carsten Braun, GeorgWellmer, Marek Behr, and Josef Ballmann

Abstract. This paper outlines the development of the aero-structural dynamics method SOFIA over the duration of the Collaborative Research Center SFB 401. The algorithms SOFIA applies for the spatial and the temporal aero-structural dynamics coupling are presented. It is described in particular how SOFIA’s load and deformation transfer algorithms suitable for non-matching grids at the coupling interface were enhanced towards the application to complete aircraft configurations. The application of SOFIA to various subsonic and transonic aeroelastic test cases is discussed.

1 Introduction

The design of high-performance wings for large commercial aircraft requires the inclusion of their aeroelastic properties into the aerodynamic and structural design process. During preliminary design, the geometry of the wing is defined as a compromise between good flight performance during take-off, landing and cruise flight on the one hand and load capacity and weight of the structure on the other hand. In an iterative fashion, the aerodynamic shape, the loads, the construction of the wing assembly and the deformation are studied sequentially and more or less independently. Aerodynamic wind tunnel testing with rigid or nearly-rigid reduced-scale models plays a key role.

But in those tests, similarity with the full scale body can only be achieved in a very limited manner, primarily with respect to the aerodynamic parameter Mach number and to a certain extent also with respect to the Reynolds number. Aeroelastic similarity is usually not achieved. Based on the aerodynamic analysis, wing loads, deformations and particularly the aerodynamic twist are determined. Then the wing geometry and construction of the wing assembly are modi- fied a posteriori so that after taking into account the static aeroelastic deformation in cruise flight sufficient lift and minimum drag are ensured.

The described design and construction procedure requires several iterations because in every step the aeroelastic coupling and the nonlinearity of the problem cannot be captured completely. Besides that, nonlinear flutter possibly occuring in the transonic flow regime cannot be predicted with such a procedure. Therefore it is necessary to develop numerical methods, which reliably predict the interaction between aerodynamic, structural and inertial forces. Such a numerical method has been progressively developed in the past four funding periods of the Collaborative Research Center SFB 401 Flow Modulation and Fluid-Structure Interaction at Airplane Wings at RWTH Aachen University. This paper gives an overview about this numerical method named SOFIA and its past and present development stages. The organization of the subsequent sections of this paper is as follows."