Numerical Study of Synthetic-Jet Actuation Effect on Airfoil Trailing Edge Noise

72 Pages·2016·13.65 MB·English

by  Marco Sansone

Dissertations and Theses
12-2015
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Marco Sansone
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Numerical Study of Synthetic-Jet Actuation Effect on
Airfoil Trailing Edge Noise
A Thesis
Submitted to the Faculty
of
Embry-Riddle Aeronautical University
by
Marco Sansone

In Partial Fulfillment of the
Requirements for the Degree
of
Master of Science in Aerospace Engineering

December 2015
Embry-Riddle Aeronautical University
Daytona Beach, Florida

1

ACKNOWLEDGMENTS

I would like to acknowledge my research teammates Lap Nguyen and Sam
Salehian for all the help and support they’ve given that has gone towards the completion
of this thesis. I’d also like to thank my advisors Dr. Vladimir Golubev and Dr. Reda
Mankbadi for their guidance and the opportunity to work on this project as well as the
patronage of the AFRL program and my Air Force advisors Dr. Crystal Pasiliao and Dr.
Daniel Reasor who helped expand the study.
2

TABLE OF CONTENTS
LIST OF TABLES .............................................................................................................. 3
LIST OF FIGURES ........................................................................................................... 4
SYMBOLS .......................................................................................................................... 6
ABBREVIATIONS ............................................................................................................ 7
ABSTRACT ........................................................................................................................ 8
1. Introduction ................................................................................................................ 9
1.1. Airfoil Noise ............................................................................................................... 9
1.2. Motivation ................................................................................................................. 13
1.3. Project History .......................................................................................................... 14
1.4. Goals of Current Study............................................................................................. 16
1.5. Procedure Overview ................................................................................................. 18
2. Numerical Experiment Setup ................................................................................... 20
2.1. Governing Equations ................................................................................................ 21
2.2. Non-Dimensionalization .......................................................................................... 23
2.3. Numerical Discretization ......................................................................................... 23
2.4. Time Marching ......................................................................................................... 25
2.5. Filtering ..................................................................................................................... 26
2.6. Computational Meshes ............................................................................................. 27
2.7. Boundary Conditions ............................................................................................... 30
3. Results-Joukowski High Speed Regime ......................................................... 32
3.1. Actuation Effects on the Flow Field ....................................................................... 33
3.2. Actuation Effects on the Surface ............................................................................. 34
3.3. Actuation Effects on Noise ...................................................................................... 39
3.4. Effect of Synthetic-Jet Actuator Location .............................................................. 48
4. Results-NACA Low Speed Regime ......................................................................... 49
4.1. Actuation Effects on the Flow Field ....................................................................... 50
4.2. Actuation Effects on the Surface ............................................................................. 55
4.3. Actuation Effects on Noise ...................................................................................... 59
5. Conclusion ................................................................................................................ 62
6. Recommendations .................................................................................................... 66
7. REFERENCES ......................................................................................................... 67
3

LIST OF TABLES

Table 2.1. Joukowski Mesh Indices. ................................................................................. 30
Table 2.2. NACA Mesh Indices. ....................................................................................... 30
Table 3.1. Joukowski Airfoil Test Case Descriptions....................................................... 33
Table 4.1. Actuation Frequencies For NACA Cases Chosen From 60% Shedding. ........ 50
Table 4.2. NACA Airfoil Test Case Descriptions. ........................................................... 50
Table 4.3. Average Lift For All NACA Cases.................................................................. 58
Table 4.4. Initial Separation Point Location For NACA Cases. ....................................... 59
4

LIST OF FIGURES
Figure 1.1. Feedback Model Proposed By (Tam, 1974). .................................................. 10
Figure 1.2. Feedback Model Proposed By (Arbey & Bataille, 1983). .............................. 11
Figure 1.3. Feedback Model Proposed By (Nash et al., 1999). ........................................ 12
Figure 1.4. Feedback Model Proposed By (Desquesnes et al., 2007). ............................. 13
Figure 1.5. Schematic Of A Synthetic-Jet Actuator. ........................................................ 15
Figure 1.6. Mean Surface Pressure On Joukowski With Upstream Gust (Sewell, 2012). 17
Figure 1.7. z-Vorticity Contours Showing Separation Bubble For Joukowski Airfoil. ... 17
Figure 1.8. Acoustic Directivities At Radius 1c (Sewell, 2012). ..................................... 17
Figure 2.1. Point 1 Boundary Stencil (Gaitonde & Visbal, 1998). ................................... 24
Figure 2.2. Point 2 Boundary Stencil (Gaitonde & Visbal, 1998). ................................... 25
Figure 2.3. Sectional Mesh Near The Airfoil Surface. ..................................................... 28
Figure 2.4. Details Of Overset Meshes In SJA Orifice Region. ....................................... 29
Figure 3.1. Average z-Vorticity Contours. ....................................................................... 33
Figure 3.2. Average Negative u-Velocity Contours Showing Recirculation. .................. 34
Figure 3.3. Instantaneous z-Vorticity Contours At SJA location At τ=121. .................... 34
Figure 3.4. Surface Pressure On Surface For Joukowski Cases. ...................................... 35
Figure 3.5. Joukowski Lift Histories................................................................................. 36
Figure 3.6. FFT Of Lift. .................................................................................................... 37
Figure 3.7. Time Derivative Of Lift Histories. ................................................................. 37
Figure 3.8. Joukowski Drag Histories. ............................................................................. 37
Figure 3.9. Mean Surface Friction Along Top Surface. ................................................... 38
Figure 3.10. Average Lift Gain For Joukowski Cases. ..................................................... 39
Figure 3.11. Prms Directivities At Radius 1c From Chord For Joukowski Cases. .......... 41
Figure 3.12. Drop In dB Levels For All Frequencies Compared To Clean Case. ............ 41
Figure 3.13. Acoustic Spectrum At Various Locations. Pfft Vs ω Scale. ........................ 42
Figure 3.14. Acoustic Spectrum At Various Locations. dB vs f Scale. ............................ 43
Figure 3.15. Acoustic Spectrum At Various Locations. Pfft Vs ω Scale. ........................ 44
Figure 3.16. Acoustic Spectrum At Various Locations. dB vs f Scale. ............................ 45
Figure 3.17. Acoustic Spectrum At Various Locations. Pfft Vs ω Scale. ........................ 46
Figure 3.18. Acoustic Spectrum At Various Locations. dB vs f Scale. ............................ 47
Figure 3.19. Directivities Of PRMS Acoustic Intensity At Radius 1c. ............................. 48
5

Figure 4.1. Average z-Vorticity Contours. ....................................................................... 52
Figure 4.2. Instantaneous z-Vorticity Contours At τ=81. ................................................. 53
Figure 4.3. Instantaneous z-Vorticity Contours At SJA Region At τ=81. ....................... 54
Figure 4.4. Pressure On Surface For NACA Cases. ......................................................... 57
Figure 4.5. Lift History For All NACA Cases At Varying AoA. ..................................... 58
Figure 4.6. Surface Friction Along The Chord For Each Angle. ...................................... 59
Figure 4.7. Acoustic Prms Directivities At Radius 1c From Chord For NACA Cases. .. 60
Figure 4.8. Acoustic Spectrum At Radius 1c Above Midchord. dB Vs f. ........................ 61
6

SYMBOLS

𝑣 Amplitude of SJA actuation
𝑚
𝐴 Area of SJA orifice
𝑐 Chord length
𝐶 Coefficient of Drag
𝑑
𝐶 Coefficient of friction
𝑓
𝐶 Coefficient of Lift
𝐿
𝐶 Coefficient of Pressure
𝑝
𝑑𝐵 Decibels
𝑆 Depth of SJA Orifice
𝑣 Exit Velocity for SJA
𝑆𝐽𝐴
𝐶 Fast Fourier Transform of Lift
𝐿𝑓𝑓𝑡
𝑃 Fast Fourier Transform of pressure signal
𝑓𝑓𝑡
𝛾 Heat capacity ratio
𝜔 Non-dimensional Actuation Frequency
𝑎
𝜔 Non-dimensional Frequency
𝜏 Non-dimensional time TAU
𝑃 Root mean square of pressure signal
𝑅𝑀𝑆
𝜉 Transformed 𝑥
𝜂 Transformed 𝑦
𝜁 Transformed 𝑧
𝜌 Upstream Density
∞
𝑀 Upstream Mach number
∞
𝑇 Upstream Temperature
∞
𝑢 Upstream Velocity
∞
7

ABBREVIATIONS

AoA Angle of Attack
CAA Computational Aero-Acoustics
DNS Direct Numerical Simulation
Hz Hertz
ILES Implicit Large Eddy Simulations
KH Kelvin-Helmholtz waves
KE Kinetic Energy
LES Large Eddy Simulations
LDA Laser-Doppler Anemometry
Pr Prandtl number
RANS Reynolds-Averaged Navier–Stokes
Re Reynolds number
SJA Synthetic-Jet Actuator
TS Tollmien-Schlichting waves
UAV Unmanned Aerial Vehicle