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Numerical Analysis of Supersonic Inlet Buzz Characteristics under Various Throttling and Angle of Attack Conditions
다양한 출구조건과 받음각이 적용된 초음속 흡입구 공력불안정성 수치적 연구

DC Field Value Language
dc.contributor.advisor김종암-
dc.contributor.author홍우람-
dc.date.accessioned2017-07-14T06:05:21Z-
dc.date.available2017-07-14T06:05:21Z-
dc.date.issued2013-02-
dc.identifier.other000000009681-
dc.identifier.urihttps://hdl.handle.net/10371/125427-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 협동과정 계산과학전공, 2013. 2. 김종암.-
dc.description.abstractThe present study numerically investigates the flow instability around supersonic inlet, called inlet buzz. Though the flow conditions change linearly, behavior of inlet buzz alters hysteretically. In order to simulate the inlet buzz hysteretic character, computations are conducted with varying mass flow rate and angle of attack. The mass flow rate condition is controlled by an exit throttling plug which moves back and forth to change an exit area. For angle of attack study, three dimensional inviscid simulations are conducted.
Firstly, a set of simulation with mass flow control is presented. This simulation focuses on hysteretic buzz characteristics of supersonic inlet according to mass flow and the historic path of the mass flow change. Before the set of simulation, an inlet without a center-body is calculated to validate basic resonance mode results. In the next, an inlet buzz case with decreasing mass flow rate is simulated. In this process, the inlet buzz characteristic changes from the first mode of a low frequency regime to the second mode of a high frequency regime. Lastly, the effect of the increasing mass flow rate on the inlet buzz is examined. This case shows another kind of the buzz transition that the buzz frequency becomes higher in the third mode. The hysteretic inlet buzz has many similarities to the fundamentals of a pipe-type musical instrument such as self-excited feed-back mechanism and overblowing. Considering the similarities, the hysteretic characteristics of an inlet buzz is discussed in the instrumental acoustic point of view.
In the second step, an investigation of angle of attack effects on inlet pressure oscillation is carried out with three-dimensional inviscid simulation intended to examine a tendency of inlet buzz briefly. It is seen that the major physical characteristic of the inlet pressure oscillation can be obtained by inviscid computations and the computed flow patterns inside and around the inlet are qualitatively consistent with the experimental observations. It is found that patterns of pressure oscillation histories and distortion due to asymmetric (or three-dimensional) shock structures are substantially affected by angle of attack. The dominant frequency of the existing inlet pressure oscillation does not change noticeably even in regards to a wide range of angle of attacks. However, the increasing angle of attack condition initiates a pressure oscillation from a steady state of inlet at low angle of attack.
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dc.description.tableofcontentsChapter I Introduction 1
1.1 Inlet Buzz Transition under Varying Mass flow condition 2
1.2 Asymmetry Behavior of Inlet Flow Oscillation at Attack Angled flow 5
1.3 Outline of Thesis 7
Chapter II Instrumental Acoustics 9
2.1 Edge Tone 10
2.2 Positive feedback 11
2.3 Over-blowing 12
Chapter III Numerical Approach 14
3.1 Governing Equations 14
3.2 Turbulence Model 19
3.2.1 The original k-ω model 20
3.2.2 The Transformed k-ε Model 20
3.2.3 The Standard Menters k-ω Shear Stress Transport (SST) Model 21
3.2.4 The Menters k-ω SST Model from 2003 (k-ω SST-2003) 24
3.3 Spatial Discretization 26
3.3.1 Roes Flux Difference Splitting 27
3.3.2 RoeM Scheme 29
3.3.3 AUSMPW+ 31
3.3.3 Higher order spatial accuracy 34
3.3.4 Compact Scheme for Viscous Fluxes 36
3.4 Time Integration Method 37
3.4.1 Pseudo-Time Discretization 38
3.4.2 LU-SGS Scheme 40
3.4.3 Dual Time Stepping 42
3.5 Geometric Modeling and Boundary Condition 44
3.5.1 Axisymmetric Inlet Modeling for Viscous Computation 44
3.5.2 Modeling of Varying Exit Area for Mass Flow Control 46
3.5.3 Three-dimensional Inlet Modeling for Inviscid Computation 47
Chapter IV Inlet Buzz Simulation with Throttling Ratio Control 50
4.1 Case1 - Validation by Inlet Configuration without Center Body 50
4.2 Case2 - Inlet under Decreasing Mass Flow (T.R) Condition 57
4.2.1 Large Throttling Ratio (2.41 ~ 1.42) 57
4.2.2 Medium Throttling Ratio (1.14 ~ 0.79) 60
4.2.3 Small Throttling Ratio (0.67 ~ 0) 64
4.3 Case3 - Inlet under Increasing Mass Flow (T.R) Condition 71
4.4 Summary of Inlet Buzz Simulation Results with Mass flow control 78
4.5 Hysteretic Behavior of inlet buzz with Varying Mass Flow Rate 80
4.5.1 Required factors for overblowing 81
4.5.2 Vortex role for resonation and relation with throttling ratio 84
Chapter V Inlet Buzz Simulation at Angle of Attacks 87
5.1 Steady State Simulation at T.R 2.41 89
5.2 Inlet Pressure Oscillation Simulation with Zero Angle of Attack 92
5.3 Inlet Pressure Oscillation Simulation with Moderate Angle of Attack 96
5.4 Angle of Attack Effects on Inlet Pressure Oscillation 105
5.4.1 Pressure oscillation transition from small to big amplitude 105
5.4.2 Dynamic Distortion 110
Chapter VI Concluding Remarks 113
References 118
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dc.formatapplication/pdf-
dc.format.extent5246166 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectCFD-
dc.subjectSupersonic inlet-
dc.subjectInlet buzz-
dc.subjectShock instability-
dc.subjectHysteretic characteristic-
dc.subjectThrottling control-
dc.subjectAngle of attack-
dc.subjectTransition-
dc.subject.ddc004-
dc.titleNumerical Analysis of Supersonic Inlet Buzz Characteristics under Various Throttling and Angle of Attack Conditions-
dc.title.alternative다양한 출구조건과 받음각이 적용된 초음속 흡입구 공력불안정성 수치적 연구-
dc.typeThesis-
dc.description.degreeDoctor-
dc.citation.pagesvii, 123-
dc.contributor.affiliation자연과학대학 협동과정 계산과학전공-
dc.date.awarded2013-02-
Appears in Collections:
College of Natural Sciences (자연과학대학)Program in Computational Science and Technology (협동과정-계산과학전공)Theses (Ph.D. / Sc.D._협동과정-계산과학전공)
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