New Results in Numerical and Experimental Fluid Mechanics VII (eBook)

Title Page 1
Foreword 5
Table of Contents 7
Numerics 7
Interfacial Area Transport Equation in Statistical-Eulerian-Eulerian Simulations of Multiphase Flow 14
Introduction 14
Flow Model 14
Implementation 16
Development of an IATE 16
Exemplary IATE: Supercritical Injection 17
Conclusion 20
References 21
Application of the Multi-Scale-Finite-Volume Method to the Simulation of Incompressible Flows with Immersed Boundaries 22
Introduction 22
Discretization of the Navier-Stokes Equations 23
Pressure Computation with the IMSFV-Procedure 24
Numerical Results 27
IMSFV for Elliptic Problems with Impermeable Regions 27
Navier-Stokes Solver with IMSFV 28
Conclusions 29
References 29
A Variable-Fidelity Modeling Method for Aero-Loads Prediction 30
Introduction 30
Framework of the Variable-Fidelity Modeling Method 31
Kriging Model and Bridge Function 32
Sample-Point Refinement Strategy 33
Results and Discussion 34
VFM for RAE 2822 with One Independent Variable 34
VFM for RAE 2822 with Two Independent Variables 36
Conclusions 37
References 38
Modelling and Validation of Covariance Transport Equations for Large-Eddy-Simulation of Ternary, Turbulent Mixing 39
Introduction 39
Motivation 40
Transport Equations 41
Scalar Dissipation Rate 42
Covariance Transport Equation and Cross-Dissipation Rate 43
Results and Conclusions 43
References 46
An Efficient One-Shot Algorithm for Aerodynamic Shape Design 47
Introduction 47
One-Shot Algorithm 49
Preconditioner B 50
Computing Derivatives 51
Treatment of Lift Constraint 52
Numerical Results 52
Conclusion 53
References 53
Application of a New Roughness Extension for k - . Turbulence Models 55
Introduction 55
Roughness Modeling 56
Results 57
Flow through a Rough Pipe (Nikuradse [8]) 57
Flow over a Rough Flat Plate (Ligrani and Moffat [5]) 58
Flow over a Rough Airfoil (Ljungström [6]) 59
Conclusion 61
References 62
Improved Wall Functions Based on the 1D Boundary Layer Equations for Flows with Significant Pressure Gradient 63
Introduction 63
Study of Dominant Terms in the Boundary Layer Equation 64
Improved Wall-Function Modelling 65
Numerical Method 66
Results 67
Conclusion 70
References 70
A Wall Model Based on Simplified Thin Boundary Layer Equations for Implicit Large Eddy Simulation of Turbulent Channel Flow 71
Introduction 71
Simplified Thin Boundary Layer Equation 72
Numerical Method 74
Results 74
Prediction Capability 75
The Effect of LES/TBLE Coupling Positions 76
Reynolds Number Dependency of Grid Resolution Requirements 76
Conclusions 78
References 78
Detached-Eddy Simulation of Supersonic Flow Past Cylindrical Aft Body with and without Base Bleed 79
Introduction 79
Numerical Methodology 80
Details of the Test Case 80
Results 81
Aft Body without Bleed 81
Aft Body with Bleed, $I$ = 0.0075 83
Conclusions 86
References 86
Prediction of the Wind Tunnel Sidewall Effect for the iGREENWing-Tailplane Interference Experiment 87
Introduction 87
Grid and Solver 88
Results 89
The NLR7301 at Mach 0.70 89
The Aerostabil Wing at Mach 0.70 92
Conclusion 93
References 94
The Influence of the Length Scale Equation on the Simulation Results of Aerodynamic Flows Using Differential Reynolds Stress Models 95
Introduction 95
Model Components 96
Reynolds Stress Equation 96
Length Scale Equation 97
Results 97
RAE 2822 Airfoil 98
ONERA M6 Wing 98
Conclusion 101
References 102
Efficient Flow Computation Including Turbulent Transport 103
Introduction 103
Governing Equations 104
Basic Solution Scheme 104
Implementation of the One-Equation Turbulence Model 106
Computational Results 106
Compressible, Turbulent Flow at Moderate Reynolds Numbers 107
Compressible, Turbulent Flow at High Reynolds Numbers 109
Incompressible, Turbulent Flow 110
Conclusion 110
References 111
Automatic Transition Prediction for Three-Dimensional Aircraft Configurations Using the DLR $TAU$ Code 112
Introduction 112
Transition Prediction Coupling 113
Computational Results 114
Conclusions 118
References 118
Numerical Simulation of the Elastic and Trimmed Aircraft 120
Introduction 120
Trim Algorithm 121
FSI Procedure and Coupling between FSI and Trim Algorithm 122
Applications 124
Conclusions 126
References 127
Chimera Simulations of Transported Large–Scale Vortices and Their Interaction with Airfoils 128
Introduction 128
Numerical Method 129
Results 130
Transported Vortices 130
NACA 0012 Airfoil 131
ONERA-A Airfoil 134
Conclusion 134
References 135
An Approach to the Gust Problem with Interfering Profiles 136
Introduction 136
Parameters and Steady Solution 137
Unsteady Subsonic and Transonic Solutions 138
Accuracy of the Unsteady Solution 143
Conclusions 143
References 144
Application of the Immersed Boundary Method for the Simulation of Incompressible Flows in Complex and Moving Geometries 145
Introduction 145
Fundamentals of Implementation 146
Surface and Domain Grids 146
Domain Identification and Marking Algorithm 146
Imposition of Boundary Conditions 147
Moving Wall Boundary Condition 148
Solving the Equation System 148
Results 148
Validation Test Cases 149
Oscillating Rectangular Prism 149
More Complex Geometries 150
Conclusion and Outlook 151
References 152
Turbulence Modeling and Detached Eddy Simulation with a High-Order Unstructured Discontinuous Galerkin Code 153
Introduction 153
Discontinuous Galerkin Schemes 154
Basic Equations 154
Turbulence Modeling 154
Turbulence Limiting 155
Detached Eddy Simulation 156
Results 156
Flat Plate Flow 156
Detached Eddy Investigation of the Flow Past a Sphere 157
Conclusion 159
References 160
An Explicit Space-Time Discontinuous Galerkin Scheme with Local Time-Stepping for Unsteady Flows 161
Introduction 161
The STE-DG Scheme for the Euler Equations 162
The Equations and the Semi-discrete Variational Formulation 162
The Space-Time Expansion Approach with Local Time-Stepping 163
Sub-Cell Shock Capturing for DG Methods 164
Troubled Cell Indicators 164
Modified Governing Equation 165
Results 165
Fluid Flow around a NACA0012 Airfoil 166
Double Mach Reflection of a Strong Shock 166
Conclusion 167
References 168
Numerical Simulation of Upstream Moving Pressure Waves in Transonic Airfoil Flow 169
Introduction 169
Numerical Method 170
Results 171
Conclusion and Outlook 175
References 175
Investigation of Resolution Requirements for Wall-Modelled LES of Attached and Massively Separated Flows at High Reynolds Numbers 177
Introduction 177
Basic Discretization and Turbulence Modelling 178
Presentation of Results for High Reynolds Number Flows 180
Turbulent Channel Flow at $Ret$ = 4800 181
Flow over a Backward-Facing Step at $Reh$=37500 181
Conclusion 183
References 184
Flow Control 9
Active Separation Control on the Flap of a Three-Element High-Lift Configuration with Segmented Actuation in Spanwise Direction 185
Introduction 186
Active Flow Control 186
Numerical Simulation Method 187
Flow Solver and Turbulence Modeling 187
Boundary Conditions 187
Time-Step Size 187
Method of Excitation 188
SCCH High-Lift Configuration 188
Results 189
Unexcited Flow 189
Excited Flow 189
Conclusion 192
References 192
Numerical Investigation of Leading Edge Blowing and Optimization of the Slot Geometry for a Circulation Control Airfoil 193
Introduction 193
Coanda Effect and Momentum Coefficient 194
$Coanda$ Effect 194
Dimensionless Momentum Coefficient 194
Numerical Airfoil Design 195
Leading Edge Blowing 196
Slot Geometry 198
Conclusion 199
References 200
Comparison of the Capability of Active and Passive Methods of Boundary Layer Control on a Low Pressure Turbine Cascade 201
Introduction 201
Profile Design 202
Passive Turbulators 202
Suction Surface Blowing 203
Experimental Setup 204
High-Speed Cascade Wind Tunnel 204
Wake Generator 204
Measurement Techniques 204
Results 205
Steady Inflow 205
Periodically Unsteady Inflow 205
Conclusions 207
References 208
Active Secondary Flow Control on a Highly Loaded Compressor Cascade by Periodically Pulsating Jets 209
Introduction 209
Experimental Setup 210
Cascade Test Rig 210
Measurement Techniques 211
Sidewall Actuator 212
Results 212
Base Flow 212
Active Flow Control 213
Conclusions 216
References 217
Simulation of Active Flow Control on the Flap of a 2D High-Lift Configuration 218
Introduction 218
Geometry and Test Case Definition 219
Computational Strategy 220
Results 221
Conclusions 225
References 225
Numerical Investigation of a Jet and Vortex Actuator (JaVA) 226
Introduction 226
Grid, Boundary Conditions and Numerical Approach 228
Results 229
Case 1, Vortex Mode 229
Case 2, Free Jet Mode 231
Case 3, Wall Jet Mode 232
Conclusions 232
References 233
Direct Numerical Simulation of Jet Actuators for Boundary Layer Control 234
Introduction 234
Numerical Method 235
Jet Vortex Generator Simulations 236
Turbulent Boundary Layer 236
Jet Vortex Generator in TBL 238
Conclusions 240
References 240
Flowfield-Characteristics Generated by DBD Plasma Actuators 242
Introduction 242
Experimental Setup 244
Post Processing 245
Results 246
Conclusions and Outlook 248
References 249
Laminar Flow Control and Transition 9
Identification and Quantification of Shear Layer Influences on the Generation of Vortex Structures 250
Introduction 250
Identification of Coherent Structures 251
Vortex Structures 251
Shear Layer Structures 252
Identification of Vortex Generation in a Shear Layer 253
Conclusion 257
References 257
Global Stability Analysis of Compressible Flow around Swept Wings 258
Introduction 258
Flow Configuration 259
Governing Equations and Numerical Method 260
Global Stability Analysis 260
DNS-Based Krylov Technique 262
Results 262
Spectrum and Global Modes 263
Influence of $Re_s$ 264
Conclusions 264
References 265
Applications of Symmetry Analysis in Stability Theory 266
Introduction 266
Symmetry Analysis 267
Symmetries Leading to the Orr-Sommerfeld-Equation 267
Additional Symmetries for the Channel Flow 268
The Channel Flow 268
Rescaling 268
Invariant Solution 269
Interpretation of Invariant Solution 270
Taylor Expansion 271
Boundary Conditions 272
Conclusion 273
References 273
Investigation on Actuator Arrays for Active Wave Control on a 2D Airfoil 274
Introduction 274
Experimental Setup and Base Flow 275
Slot and Membrane Actuator Arrays 276
Membrane Actuator for Flight Experiments 279
Conclusion 280
References 281
Experimental Flow Studies on Separation and Reattachment in the Vicinity of Sharp,Wedge Shaped Leading Edges at Low Reynolds Numbers 282
Introduction 282
Experimental Setup 283
Wind Tunnel 283
Wedge Profile Models 284
Measurement and Flow Visualisation Techniques 284
Results and Discussion of the Results 285
Formation and Size of the Separation Bubble 285
State of the Boundary Layer 287
Laminar Reattachment 288
Conclusion 288
References 289
Receptivity Considerations for Cascaded Actuators Generating Tollmien-Schlichting Waves 290
Introduction 290
Objective 290
Previous Investigations 291
Method 291
Wall-Velocity Actuation 291
Receptivity Considerations 291
Actuator Design 292
Discussion of Different Design Parameters 294
SlotWidth Ratio . 294
Phase Parameter . 295
Number of Actuators 296
Length per Actuator Element 297
Conclusions 297
References 297
Numerical Investigation of Transition Control by Porous Surfaces in Hypersonic Boundary Layers 298
Introduction 298
Numerical Approach 299
Direct Numerical Simulation 299
Linear Stability Theory 299
Grids and Initial Solutions 300
Results 300
Validation for a Smooth Wall 300
Mack Mode Stabilisation by Porous Surfaces 301
Spatial Linear Stability Theory at a Blunt Cone 303
Conclusion 304
References 305
Investigation of Laser Generated Perturbations for Boundary Layer Stability Experiments 306
Introduction 306
Experimental Setup 307
Results 308
Boundary Layer Instabilities at Natural Transition 308
Boundary Layer Instabilities with Artificial Disturbances 309
Conclusion 312
References 313
Experimental Simulation and Test Techniques 10
Eulerian and Lagrangian Insights into a Turbulent Boundary Layer Flow Using Time Resolved Tomographic PIV 315
Introduction 315
Test Set-Up and Procedure 316
Results 318
Instantaneous 3D-3C(t) Velocity Vector Fields 318
Conditional Averaging 319
Lagrangian Approach 320
Conclusions and Outlook 321
References 321
An Automated Test Section for the Experimental Optimization of Multi-element High-Lift Systems 323
Introduction 323
Experimental Set-Up 324
Balance 324
Eccentric Traverse 325
Test Section 327
Results 327
Systematic Analysis 327
Optimization 328
Conclusion 330
References 330
Application of Pressure-Sensitive Paint for Determination of Dynamic Surface Pressures on a 30 Hz Oscillating 2D Profile in Transonic Flow 331
Introduction 331
Model and Test Facility 332
Unsteady Pressure-Sensitive Paint 333
Development of Unsteady Pressure-Sensitive Paints 333
Dynamic Calibration of PSP 333
Data Acquisition 334
Phase Locked Unsteady PSP Data Acquisition 334
Unsteady PSP Data Acquisition 335
Triggering the Data Acquisition System 335
Data Reduction 335
Results for the NLR7301 Model 336
Conclusion 338
References 338
Simultaneous Measurements of Unsteady Aerodynamic Loads, Flow Velocity Fields, Position and Wing Deformations of MAVs in Plunging Motion 339
Introduction 339
Experimental Environment 340
Optical Measurement Techniques 341
MAV Wing Preparation 341
Optical Setups at Test Section 341
Data Evaluation 342
Results 343
Static Measurements 343
Effects of Wing Flexibility and Plunging Motion 344
Conclusion 346
References 346
Development of a Thermo-Optical Sensor for Measurements ofWall Shear Stress Magnitude and Direction 347
Introduction 347
Numerical and Experimental Setup 348
Numerical Results 349
Experimental Results 351
Conclusion 352
References 354
Flow–Induced Oscillation of a Flat Plate – A Fluid–Structure–Interaction Study Using Experiment and LES 355
Introduction 355
Solution Method 356
Experiment 356
Simulation 357
Results 358
Conclusions and Outlook 361
References 362
Investigations to the Response Time of a Glued Thermocouple on the Basis of Experimental and Numerical Analyses 363
Introduction 363
Experimental Investigations 363
Dipping-Experiment 364
VxG-Experiment 365
Numerical Investigations 366
Sensitivity Analysis 366
Coupled Simulation of the VxG-Experiment 367
Conclusions 370
References 371
Hypersonic Flows and Aerothermodynamics 11
Shock Tunnel Experiments and CFD Simulation of Lateral Jet Interaction in Hypersonic Flows 372
Introduction 372
Experimental Tools 373
Shock Tunnel STA of ISL 373
Missile Mock-Up 374
Measurement Techniques 374
Experimental Results 375
CFD Simulation 377
CFD Code 377
Calculated Interaction Amplification Factors 378
Conclusions 379
References 379
Heat Transfer at the Nose of a High-Speed Missile 380
Introduction 380
Experiments 381
Shock Tunnel Facilities 381
Heat Flux Measurement 382
Experimental Results for M = 6 383
Summary of the Experimental Results for M = 3.5 up to M = 10 385
Conclusions 387
References 387
Analysis of Jet Thruster Control Effectiveness and the Interaction with Aerodynamic Surfaces for a Slender Cylindrical Missile 388
Introduction 388
Geometry 389
Test Campaign 391
Numerical Solution 392
Analysis 393
References 395
New Explanation of Noise Production by Supersonic Jets with Gas Dredging 396
Introduction 397
w - Mach Waves 398
New Approach to the Jet Boundary Layer Structures 399
General Considerations 399
The w' -Mach Waves 400
The w' ' -Mach Waves 401
Conclusions 402
References 403
Pattern Recognition in High Speed Schlieren Visualization at the High Enthalpy Shock Tunnel Göttingen (HEG) 405
Introduction 405
Experimental Conditions 406
Measurements in Visualizations 406
Visual Data Manipulator 407
Results and Discussion 408
Shock Stand-Off Distance Measurement for Cylinder Model 408
Shock Angle Measurement in Scramjet Combustion Chamber 409
Model Displacement Tracking for Force Prediction in HEG Flow 411
Conclusions 411
References 412
Preliminary Design of a Mach 6 Configuration Using MDO 413
Introduction 413
Reference Design Configuration 414
MDO Tool 414
Geometry Generation 415
FEM Calculation 416
Mass Estimation 416
CFD Grid Generation 416
CFD TAU Calculation 417
Force and Trim Calculation 418
Objective Function and Constraints Handling 418
Optimizer 419
MDO Applications 419
Conclusions 420
References 420
Numerical Investigation of the Isolator Flow Field of a SCRAMJET Engine with Elevated Wall Temperatures 421
Introduction 421
Numerical Tool 422
Free Stream Conditions 422
Model Geometry and Outer Compression 423
Inflow Profiles at the Isolator Entrance 423
Isolator Flow Field 425
Conclusion 427
References 427
Numerical Simulation of Nozzle Flow into High Vacuum Using Kinetic and Continuum Approaches 429
Introduction 429
Nozzle Expansion 430
Numerical Methods and Problem Approach 430
Determination of Interface Conditions 431
Reference Case 433
Results 433
Near Field Results 433
Far Field Results 434
Conclusion 435
References 436
Advanced Flight Analysis of SHEFEX-I 437
Introduction 437
General Comments 438
Numerical Investigations 438
Sensitivity Analysis 440
Numerical Results of the Re-entry 441
Conclusions 444
References 444
Analysis of the Heat Transfer in Liquid Rocket Engine Cooling Channels 446
Introduction 446
Numerical Methods 447
Roughness Modelling 447
Dense Gas Properties 448
Coupling of Computational Codes 449
Results 449
Panel Test Case Results 450
Sensitivity Analysis 450
Summary 451
References 452
Aeroacoustics 12
Analysis of High-Lift Generated Noise via a Hybrid LES/CAA Method 454
Introduction 454
Numerical Methods and Computational Setup 455
Large-Eddy Simulation 455
Acoustic Simulation 455
Results 456
References 460
Acoustics and Turbulence Related to the Flow over a Flexible Plate Structure behind an Obstacle 462
Introduction 462
Model Setup 463
Experimental Method 464
Numerical Method 464
Results 465
Measured Sound Radiation 465
Fluid-Structure Interaction 466
Simulated Sound Radiation 468
Conclusion 469
References 469
Large–Eddy Simulation of Three–Dimensional Cavity Flow Using a Time–Conservative Finite–Volume Method 470
Introduction 470
Numerical Methodology 471
Subgrid–Scale Modeling for Compressible Turbulent Flows 471
Time–Conservative Finite–Volume Method 472
Test Case: Rectangular Cavity Flow 474
Results and Discussion 475
Conclusions 476
References 477
A Hybrid Method for CAA 478
Introduction 478
The Used Codes 478
PIANO 478
NoisSol 479
Grid Coupling 479
Setting of the Ghost Points 479
Setting of the Ghost Cells 480
Time Step Coordination 482
Process Management 482
Convergence Test 483
Conclusions 485
References 485
Aerodynamic and Aeroacoustic Analysis of Contra-Rotating Open Rotor Propulsion Systems at Low-Speed Flight Conditions 486
Introduction 486
Geometry and Test Case Definition 487
Simulation Approach 487
Aerodynamic Analysis 488
Aeroacoustic Analysis 490
Conclusion and Outlook 492
References 493
Computation of Trailing Edge Noise with a Discontinuous Galerkin Method 494
Introduction 494
Theory 495
Particularly Employed Form of APE 495
Discretization of APE via DGM 495
Computations 496
Test Setup 496
Results 497
Conclusions 500
References 500
Biomedical Flows 12
Towards Numerical Simulation and Analysis of the Flow in Central Airways 502
Initial Situation and Objectives 502
Workflow and Configurations 503
Numerical Approach and Parameters 504
Results 505
Conclusion and Outlook 508
References 509
Protective Artificial Lung Ventilation: Impact of an Endotracheal Tube on the Flow in a Generic Trachea 510
Introduction 510
Experimental and Numerical Setup 511
Generic Model of the Trachea and the First Bifurcation 511
Numerical Methods: DLR THETA Code 512
Endotracheal Tube and Its Impact on the Flow Field 512
Comparison of Experimental and Numerical Results 513
Impact of Tube Model Geometry on the Resulting Flow Field 514
Conclusion 516
References 517
Numerical Simulation of Nasal Cavity Flow Based on a Lattice-Boltzmann Method 518
Introduction 518
Geometry Reconstruction 519
The Lattice-Boltzmann Method 520
Results 521
Conclusions 523
References 524
Simulation of the Flow in a Human Nose 526
Introduction 526
Numerical Method 527
Results 527
Grid Generation and Adaptation 527
Unsteady Simulation 528
Fluid Mixing 531
Conclusion 532
References 533
Airplane Aerodynamics 13
Aerodynamics of the Wing/Fuselage Junction at an Transport Aircraft in High-Lift Configuration 534
Introduction 534
Numerical Method, Geometry and Meshes 535
Results 535
Conclusion 541
References 541
Numerical and Experimental Investigation of a Stalling Flow-Through Nacelle 542
Introduction 542
Experimental Setup 543
Transition Tripping Method 543
Numerical Method 544
The Near-Wall $e^h$-Reynolds Stress Model 544
Numerical Setup for the Nacelle Computations 545
Comparison of Experimental and Numerical Results 546
Conclusions 548
References 549
Minimal Induced Drag for Non-planar Lifting Surfaces with Moderate and Small Aspect Ratio 550
Introduction 550
Background 551
Geometry, Flow Conditions and Used Numerical Methods 553
Results 554
Conclusion 556
References 557
Convection and Mixing 13
Vortex-Generator Pairs for Vortex-Induced Heat-Transfer Enhancement in Heat-Exchanger Channels 559
Introduction 559
Related Work 560
The Generic Vortex-Generator-Pair Configuration 561
The Numerical Simulation Setup 562
Configurations and Dominant Thermal Flow Structures 563
Heat-Transfer Performance Evaluation 564
Conclusion 565
References 566
Radiation Heat Transfer in Mixed Convection Flows 567
Introduction 567
The Governing Equations and the Numerical Method 568
Surface Heat Radiation 569
Results 570
Conclusions 573
References 573
Flow Structure Formation of Turbulent Mixed Convection in a Closed Rectangular Cavity 575
Introduction 575
Dimensionless Parameters 576
Experimental Setup 576
Results 578
Forced Convection 578
Mixed Convection 579
Comparison of Flow Structures 580
Conclusion 582
References 582
Miscellaneous 13
Numerical Determination of Nozzle Admittances in Rocket Engines 583
Introduction 583
Numerical Method 584
Boundary Condition for the Nozzle Head 584
Determination of the Decay Coefficient 585
Comparison of Nozzle Admittances 587
Conclusion 589
References 589
Analysis of Vertical AxisWind Turbines 591
Introduction 591
Aerodynamic Model 592
Computational Model 593
Results 593
Two Dimensional Rotor Approximation 594
Moving and Oscillating Airfoil 595
Three Dimensional Rotor Simulations 597
Conclusions 598
References 598
Numerical Analysis of the Influence of Tip Clearance Width in a Semi Open Centrifugal Compressor 599
Introduction 599
Tip Clearance Flows 600
Dimensional Analysis in Turbomachines 600
Numerical Model and Problem Setup 601
Results 602
Influence of Tip Clearance on Pressure Rise 603
Influence of Tip Clearance on Shaft Power 604
Flow Inside the Tip Clearance 604
Conclusions 605
References 606
Aerodynamic Analysis of a Helicopter Fuselage 607
Introduction 607
Numerical Setup 608
Experimental Setup 609
Results 610
Grid Study 610
Flow Topology 612
Conclusions 613
References 614
Truck Interference Effects on a Car during an Overtaking Manoeuvre: A Computational Study 615
Introduction 615
Experimental Setup 616
Computational Method 616
Results and Discussion 620
Conclusions 622
References 622
Author Index 624