Modern Aerodynamic Methods

for Direct and Inverse Applications

 

 

by

 

Wilson C. Chin, Ph.D., M.I.T.

Houston, Texas

 

November 2018

 

 

Preface

I am privileged to write this monograph, one focused on ideas new and old, but through it all, a book aimed at conveying new approaches to students and making it simple. In doing so, I want to teach important and subtle ideas while sparing the jargon Ė and provide readers with usable and down-to-earth programming tools to evaluate new approaches.

All of this, I am adept in. With no shortage of exposure to confusion, bewilderment and getting lost. At Caltech, where I earned my Masterís, I studied with Gerald Whitham, the aerodynamicist renown for "sonic boom" modeling, while at M.I.T., where I did my Ph.D., I worked with Marten Landahl, the leading pioneer in transonic flow. My exposure to aerodynamics was good but I was compelled to learn fast. But interestingly, by the time I met Whitham and Landahl, both had moved on to hydrodynamic stability. So Iíd struggle with that too, extending Whithamís kinematic wave theory to second-order, and learning the intricacies behind applied math and nonlinear equations.

I had never programmed nor touched a computer, remarkably. Not even Fortran, the mainstay of engineering. Completely alien. All I knew were differential equations and differential equations. On my first day at Boeing, I asked my supervisor, Paul Rubbert, who also worked with Landahl for his doctorate, "What kind of answers do computers give?" Sarcastically, he replied, "Any answers you want." Strange, I thought, but I would gradually appreciate those words of wisdom.

Whereas Rubbertís group focused on panel methods, Hideo Yoshihara (my second boss) and his team specialized in transonic flow Ė wow, the world sure was small. I learned a lot during the two years I worked at Boeing, publishing almost two dozen papers that probed the depths of fluid dynamics. And I would move to Pratt & Whitney Aircraft as Manager of Turbomachinery, applying new-fangled methods in transonic flow analysis to the innards of turbines and compressors. Here, Iíd also share a cubicle with Richard Whitcomb, the leading authority on supercritical wing design, winglets and Coke bottles, during six long months as we labored days on end to refine Prattís engine and airframe integration efforts. Were it not for the pungent cigars he smoked, everything would have been perfect.

But I would not stay long. That defining year, I accepted new challenges with the petroleum industry Ė at latest count, more than two decades in oil and gas exploration, where Iíd author more than twenty books with John Wiley & Sons and Elsevier Science, earn about four dozen patents, write over a hundred papers. My fascination with aerodynamics, however, had never died. The feeling goes on. I want to continue the research I once enjoyed and encourage their application in airplane design, to develop smarter models, to learn from a thriving industry as the world takes a renewed interest in subsonic, transonic and supersonic flow. Itís an exciting world and getting better by the minute.

Itís great to be back.

 

Wilson C. Chin, Ph.D., M.I.T.

Houston, Texas

Email: wilsonchin@aol.com

Phone: (832) 483-6899

 

November 2018

 

 

 

 

 

 

 

 

Acknowledgements

The subject matter, insights and perspectives in this book were conceived years ago during my aerospace studies at Caltech and M.I.T. and subsequent affiliation with Boeing and Pratt & Whitney Aircraft. Conversations and lengthy discussions with Fritz Bark, Judson Baron, Francis Edward Ehlers, Marten Landahl, Harvard Lomax, Thomas Matoi, Donald Rizzetta, Paul Rubbert, Richard Whitcomb, Gerald Whitham, Sheila Widnall and Hideo Yoshihara were particularly helpful and molded my initial approaches to aerodynamics and fluid mechanics.

Funding agencies that supported my early career work were several, including Air Force Office of Scientific Research (AFOSR), National Science Foundation (NSF), Office of Naval Research (ONR), and later, the United States Department of Energy (DOE). I also thank the Kungliga Tekniska högskolan (KTH Royal Institute of Technology) in Stockholm, Sweden, which hosted and supported my early fluid mechanics training and provided me with lasting and kind memories.

As usual, many thanks to Phil Carmical, Acquisitions Editor and Publisher, for his interest in my varied scientific activities, first petroleum and now aerospace, and for his unwavering faith and confidence that I would not compose anything too terribly incorrect. And lastly, I express my gratitude to Jenny Zhuang, my friend and companion, for discovering these almost forgotten jewels from my academic past and encouraging me to share them with similarly curious fluid-dynamicists and aerospace engineers.