INTERACTION BETWEEN A CONICAL SHOCK WAVE AND A PLANE COMPRESSIBLE TURBULENT BOUNDARY LAYER AT MACH 2.05 BY JASON T. HALE THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Aerospace Engineering in the Graduate College of the University of Illinois at Urbana-Champaign, 2014 Urbana, Illinois Advisers: Professor Gregory Elliott Professor J. Craig Dutton ABSTRACT The interaction between an impinging conical shock wave with a plane compressible turbulent boundary layer has been studied at Mach 2.05. Surface oil flow and pressure-sensitive paint (PSP) data were obtained beneath the oncoming boundary layer, while schlieren and particle image velocimetry (PIV) data were obtained in the streamwise/wall-normal (x-y) plane. Oil flow data suggested that the interaction causes two-dimensional (2D) separation near the centerline, and outside of this region three-dimensional (3D) separation that propagates fluid away from the centerline toward the sidewall. PSP results showed relatively constant upstream-influence length across the inviscid shock trace. PSP also revealed significant spanwise and streamwise expansion just downstream of the shock trace, unlike the qualitatively similar two-dimensional, wedge-generated oblique shock/boundary-layer interaction. Schlieren data suggested that the flow through the interaction was unseparated, and that there is significant unsteadiness in interaction position away from the centerline due to variation in the incoming boundary layer. PIV data showed the convection of large-scale vortical structures at velocities on the order of the streamwise velocity at the vortex center. These structures were smoothed out in the interaction. The PIV data moreover confirmed the downstream expansion shown by the PSP as well as a mean lack of flow separation. However, PIV suggested that there were some cases of instantaneous separation. Overall, the interaction diverts fluid away from a low pressure zone a little way downstream of the shock. Ultimately, the geometric three-dimensionality of the problem manifests as a preferred three-dimensionality of fluid transport next to the wall, unlike the qualitatively similar, 2D oblique shock-wave/boundary-layer interaction. ii ACKNOWLEDGEMENTS Although this thesis has a single author listed, it would be remiss to attribute the work to only one person. Without much encouragement, it would not stand as it does today. First of all, I want to thank my parents, Wes and Polly, for their loving support in all areas and times of life. I’m proud to have my parents as two of my best friends. Secondly, I want to thank my advisers Professors Greg Elliott and Craig Dutton for being patient with me and giving me the chance to work with them on this particularly engaging subject matter. Third, I would like to thank the Department of Aerospace Engineering here for granting me a Stillwell fellowship and the teaching assistantships that made this endeavor financially possible. Fourth, I want to thank Erik and Mackenzie—you are two perpetual sources of optimism, support, and encouragement in all of life’s scope. Fifth, I want to thank Jack, Nathan, Tiffany, and Drew for pursuing science with me inside and outside the classroom—you are a daily reminder that science and engineering are a team sport. Todd Reedy, Tommy Herges, Rebecca Ostman, Ruben Hortensius, Nachiket Kale, Marianne Monastero, Jeff Diebold, Brent Pomeroy, Phil Ansell—thank you for quickly befriending me at graduate school and for the priceless direction you provided. Lastly, I want to thank Meredith Walker, Bob Bunton, Jeff Wallace, Nate Hoffmann, Brad Edwards, Steve Wille, and Leslie Millar at the Office of Technology Management for demonstrating to me how technology, law, and business can intersect today to make better products for society tomorrow. iii TABLE OF CONTENTS LIST OF VARIABLES ............................................................................................................. VI PREFACE .......................................................................................................................... VIII CHAPTER 1: INTRODUCTION .............................................................................................. 1 1.1 Basic Physics of Interaction ........................................................................................ 1 1.2 Application Areas ............................................................................................................ 2 1.3 Purpose ................................................................................................................................ 3 1.4 Review of Literature ...................................................................................................... 4 CHAPTER 2: FACILITY ........................................................................................................ 6 2.1 Wind Tunnel Operation ................................................................................................ 6 2.2 Wind Tunnel Control ..................................................................................................... 8 2.3 Incoming Boundary Layer ........................................................................................ 10 CHAPTER 3: EXPERIMENTAL METHODS .......................................................................... 14 3.1 Schlieren Background and Theory ....................................................................... 14 3.2 Schlieren Methods and Experimental Setup .................................................... 18 3.3 Surface Oil Flow Methods ......................................................................................... 20 3.4 PSP Background and Theory ................................................................................... 20 3.5 PSP Methods ................................................................................................................... 22 3.6 PIV Theory....................................................................................................................... 27 3.7 PIV Methods ................................................................................................................... 29 CHAPTER 4: RESULTS ....................................................................................................... 33 4.1 Inviscid Results ............................................................................................................. 33 4.2 Oil Flow Results ............................................................................................................ 34 4.3 Schlieren Results .......................................................................................................... 38 4.4 Pressure Tap Results .................................................................................................. 44 4.5 Pressure-Sensitive Paint Results ........................................................................... 46 4.6 Particle Image Velocimetry Results ..................................................................... 51 iv CHAPTER 5: SUMMARY AND CONCLUSIONS ...................................................................... 62 5.1 Summary .......................................................................................................................... 62 5.2 Conclusion ....................................................................................................................... 63 5.3 Future Work ................................................................................................................... 63 REFERENCES ..................................................................................................................... 64 APPENDIX A: PIV UNCERTAINTY ..................................................................................... 68 APPENDIX B: NEW LABVIEW CONTROL LAW AND GENERAL OVERVIEW ...................... 71 B.1 New Control Law .......................................................................................................... 71 B.2 General Layout of LabVIEW Program ................................................................. 74 APPENDIX C: STING DESIGN ............................................................................................. 78 APPENDIX D: WIND TUNNEL SAFETY AND OPERATION .................................................. 82 D.1 Safety ................................................................................................................................. 82 D.2 Operating Procedure .................................................................................................. 83 APPENDIX E: PIV PROCESSING AND IMAGE FORMATTING .............................................. 88 E.1 Processing in DaVis: Tips and Tricks ................................................................... 88 E.2 Post-Processing in MATLAB .................................................................................... 94 APPENDIX F: SHORT AND EXTENDED NETSCANNER CALIBRATION PROCEDURE ............ 98 F.1 Front Matter ................................................................................................................... 98 F.2 Extended Calibration Directions............................................................................ 99 v LIST OF VARIABLES a = Sun-Childs parameter A = Sun-Childs parameter A(T) = pressure-sensitive-paint 0th order coefficient B = Sun-Childs parameter B(T) = pressure-sensitive-paint 1st order coefficient c =