Pitt | Swanson Engineering
Distinguished Lecturer - Earl H. Dowell (September 10, 2019)
Sep
10
2019
Distinguished Lecturer - Earl H. Dowell (September 10, 2019)
September 10, 2019 | 10:00 AM - 11:00 AM | 102 BEH

FLUID/STRUCTURAL/THERMAL/DYNAMIC INTERACTION (FSTDI) IN HYPERSONIC FLOW: COMPUTATIONAL MODELS AND EXPERIMENT

Date: 9/10/2019 Time: 10:00 AM Location: 102 BEH
Dr. Earl H. Dowell

ABSTRACT

 

Hypersonic flight is a major challenge and substantial efforts are currently underway to provide the understanding and technology required to design and operate effectively and safely a hypersonic aircraft for commercial or military purposes. Ivett Leyva [1] has recently described the essence of this challenge in an article in Physics Today, November 2017.

 

There are several key physical phenomena that can occur in hypersonic flight that involve fluid/structural/thermal/dynamics interaction (FSTDI). This talk is an effort to bring some order to this complex multidisciplinary topic.  Issues involving only two disciplines are identified that need further work as well as issues that are relatively well understood. Then the discussion moves to issues involving three disciplines (FSDI) and finally to FSTDI in its full four discipline form.

 

To bring some order to the complexity the focus of the talk will be on (1) response of structures to known turbulent flows, (2) global dynamic instability of the flow field due to shock wave/ boundary layer interaction, (3) dynamic  instability of the combined fluid structural system (flutter and limit cycle oscillations), and (4) effects of thermal fields on the foregoing and vice versa.

 

The number of non-dimensional parameters that can affect these physical phenomena is large. These non-dimensional parameters include the following: Mach Number, Reynolds Number, the ratio of flow dynamic pressure to structural stiffness, the ratio of fluid mass to structural mass, the ratio of static pressure loading to structural stiffness, and the ratio of thermal stress induced by a temperature difference between the flexible structure and its surrounding structure to flexible structure stiffness as well as the geometry (e.g. length to width ratio) of the structure. When multiple disciplines are involved the number of relevant non-dimensional parameters is indeed daunting. Thus theory and computation are very much needed as a valuable guide to the design and interpretation of experiments.

 

BIOGRAPHY

 

Dr. Dowell is an elected member of the National Academy of Engineering, an Honorary Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and a Fellow of the American Academy of Mechanics and the American Society of Mechanical Engineers. He has also served as Vice President for Publications and member of the Executive Committee of the Board of Directors of the AIAA; as a member of the United States Air Force Scientific Advisory Board; the Air Force Studies Board, the Aerospace Science and Engineering Board and the Board on Army Science and Technology of the National Academies; the AGARD (NATO) advisory panel for aerospace engineering, as Presi-dent of the American Academy of Mechanics, as Chair of the US National Committee on Theoretical and Applied Mechanics and as Chair-man of the National Council of Deans of Engineering. From the AIAA he has received the Structure, Structural Dynamics and Materials Award, the Von Karman Lectureship the Crichlow Trust Prize and the Reed Aeronautics Award; from the ASME he has received the Spirit of St. Louis Medal, the Den Hartog Award and Lyapunov Medal; and he has also received the Guggenheim Medal which is awarded jointly by the AIAA, ASME, AHS and SAE. He has served on the boards of visitors of several universities and is a consultant to government, industry and universities in science and technology policy and engineering education as well as on the topics of his research. Dr. Dowell research ranges over the topics of aeroelasticity, nonsteady aerodynamics, nonlinear dynamics and structures. In addition to being author of over three hundred research articles, Dr. Dowell is the author or co-author of four books, "Aeroelasticity of Plates and Shells", "A Modern Course in Aeroelasticity", "Studies in Nonlinear Aeroelasticity" and “Dynamics of Very High Dimensional Systems”. His teaching spans the disci-plines of acoustics, aerodynamics, dynamics and structures. Dr. Dowell received his B.S. degree from the University of Illinois and his S.M. and Sc.D. degrees from the Massachusetts Institute of Technology. Before coming to Duke as Dean of the School of Engineering, serving from 1983-1999, he taught at M.I.T. and Princeton. He has also worked with the Boeing Company.

 

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