 | Schlegat T. Experimental investigation of rarefaction effects on aerodynamic coefficients of slender and blunt re-entry vehicles: Diss. … Dr. rer. nat. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Aerodynamik und Strömungstechnik, Göttingen. – Köln: DLR, 2016. - 134 p.: ill., tab. - (Forschungsbericht; 2016-23). - Res. also Germ. - Bibliogr.: p.113-118. - ISSN 1434-8454
Шифр: (Pr 1120/2016-23) 02
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Abstract ........................................................ I
Zusammenfassung ................................................ II
Erklдrung ..................................................... III
Table of Contents ............................................... V
List of Figures ............................................... VII
List of Tables ................................................. XI
Abbreviations ................................................. XII
Nomenclature ................................................... XV
1 Introduction ............................................... 1
1.1 Hypersonic High Altitude Flight ............................ 1
1.2 High Lift / Drag Design .................................... 4
1.3 Established Prediction Methods ............................. 6
1.4 Investigation of Rarefaction Effects - Present Status and
Aim of Analysis ............................................ 9
2 Characteristics of Rarefied Flow .......................... 11
2.1 Definition of Rarefied Flow ............................... 11
2.2 Molecule Surface Interaction .............................. 12
2.3 Similarity Parameters ..................................... 13
2.4 Mach Number Independence Principle ........................ 17
3 Test Facility V2G ......................................... 19
3.1 Operating Principle ....................................... 19
3.2 Standard Measurement Technique ............................ 22
3.3 Supplemental Measurement Devices and Test Article
Support ................................................... 23
3.4 Force Balance ............................................. 24
3.4.1 Requirements and Design Limitations ................ 24
3.4.2 Load Determination ................................. 26
3.4.3 V2G Strain Gauge Balance Principle ................. 27
3.4.4 Design & Concept ................................... 28
3.4.5 V2G Strain Gauge Circuitry ......................... 28
3.4.6 V2G Force Measurement Technique .................... 30
3.4.7 Analytical Approach ................................ 32
3.5 Test Article Design ....................................... 36
4 Preparation of Experiments ................................ 40
4.1 Facility Setup ............................................ 40
4.2 Test Article Selection .................................... 40
4.3 Determination of Operating Conditions ..................... 43
4.4 Radial and Axial Pitot Pressure ........................... 46
4.5 Test Matrix Definition .................................... 50
4.6 Model Support ............................................. 53
4.7 Balance Improvements ...................................... 54
4.8 Balance Calibration ....................................... 58
5 Performance of Force Measurements ......................... 61
5.1 Procedure ................................................. 61
5.2 Measurements .............................................. 64
5.3 Evaluation ................................................ 65
6 Rarefaction Effects ....................................... 72
6.1 Comparison at Constant Reynolds Number .................... 72
6.1.1 Aerodynamic Coefficients versus Angle of Attack
at Constant Reynolds Numbers ....................... 72
6.1.2 Aerodynamic Coefficients versus Knudsen Number at
Constant Angles of Attack .......................... 79
6.1.3 Aerodynamic Coefficients versus Rarefaction
Parameter at Constant Angles of Attack ............. 87
6.1.4 Assessing Mach and Reynolds Number Effects ......... 92
6.1.5 Comparing Effects of Rarefaction of Both Test
Configurations ..................................... 95
6.2 Comparison at Constant Knudsen Number ..................... 99
6.3 Comparison Flow Inhomogeneity at Constant Reynolds
Number ................................................... 103
7 Summary .................................................... 108
8 Outlook and further Use for Numerical Comparisons .......... 111
9 Acknowledgements ........................................... 112
10 References ................................................. 113
Appendix A - General Facts, Specifications and Derivations .... 119
Appendix В - Rarefaction Effects .............................. 123
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