 | Wagner A. Passive hypersonic boundary layer transition control using ultrasonically absorptive carbon-carbon ceramic with random microstructure: [Diss.] / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Aerodynamik und Strömungstechnik, Göttingen. - Köln: DLR, 2014. - xiii, 118 p.: ill. - (Forschungsbericht; 2014-31). - Bibliogr.: p.99-111. - ISSN 1434-8454
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Abstract ...................................................... iii
List of Figures ................................................ xv
List of Tables ................................................ xxi
1 Introduction ................................................. 1
1.1 Hypersonic Boundary Layer Transition .................... 3
1.1.1 Path to Transition ............................... 3
1.1.2 Streamwise Instabilities ......................... 4
1.1.3 Linear Stability Theory .......................... 7
1.2 Hypersonic Transition Control ........................... 8
1.3 Scope of the Study ..................................... 10
2 Methodology ................................................. 11
2.1 The High Enthalpy Shock Tunnel Göttingen (HEG) ......... 11
2.1.1 Overview ........................................ 11
2.1.2 Operating Principle ............................. 13
2.2 The High Enthalpy Shock Tunnel HIEST ................... 15
2.3 Model and Instrumentation .............................. 16
2.3.1 Wind Tunnel Models .............................. 16
2.3.2 Instrumentation ................................. 20
2.4 Calibration of HEG Free-Stream Conditions .............. 23
2.4.1 Free-Stream Quantity Measurements ............... 23
2.4.2 Computational Verification ...................... 25
2.4.3 Validation ...................................... 30
3 Ultrasonically Absorptive Carbon-Carbon ..................... 32
3.1 Manufacturing and Basic Properties ..................... 33
3.2 Pore Filling Time ...................................... 36
3.2.1 Choked Flow ..................................... 36
3.2.2 Subsonic Flow ................................... 38
3.2.3 Pore Filling Times at HEG Test Conditions ....... 39
3.3 Absorber Properties - Theory ........................... 41
3.3.1 Homogeneous Absorber Theory ..................... 42
3.3.2 C/C Absorption Characteristics .................. 44
3.4 Absorber Properties - Experiment ....................... 49
3.4.1 Test Rig ........................................ 49
3.4.2 Evaluation Routine and Results .................. 50
4 Experimental Results ........................................ 54
4.1 Experiments on Cone Configurations with Solid Surface .. 54
4.1.1 Transition Experiments in HEG and HIEST - an
Intercomparison ................................. 55
4.1.2 Nose Bluntness Effects .......................... 60
4.1.3 Second Mode Instabilities ....................... 63
4.2 Experiments on Cone Configurations with Porous
Surface ................................................ 69
4.2.1 Transition Delay ................................ 69
4.2.2 Second Mode Damping ............................. 75
4.2.3 Second Mode Amplification Rate .................. 79
5 Discussion .................................................. 84
6 Conclusion .................................................. 90
A Appendix .................................................... 93
Bibliography ................................................... 99
Curriculum Vitae .............................................. 113
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