Introduction to Shock-Wave Boundary-Layer Interactions


This course introduces the basics of shock-wave/boundary-layer interactions (SBLIs). It begins a very brief revision of fundamental fluid mechanics, in particular gasdynamics and boundary layers. This is followed by an explanation of the different types of SBLIs before describing in more detail the fundamental flow physics of a number of nominally 2-dimensional interactions. The difference between attached and separated interactions is discussed and some basic criteria for the prediction of the separation onset are described.

In the second part of the course 3-dimensional interactions are introduced in greater detail, concentrating on flow topology and key physics (inc. unsteadiness). This is followed by an overview of flow control techniques, distinguishing between boundary-layer and shock control methods and explaining the relative objectives and merits of each approach. Finally, recent research into the influence of corner flows on nominally 2-dimensional interactions is described.

Key Topics 

  • Revision of relevant fluid mechanics knowledge
  • Understanding of the different scenarios where SBLIs occur
  • Detailed knowledge of fundamental 2- and 3-dimensional SBLIs, including flowfield topology, flow variables, separation and unsteadiness
  • An understanding of current state-of-the-art of flow control relevant to SBLI (function, efficacy and potential)
  • An understanding of more complex 3-dimensional effects

Who Should Attend

For professionals (and students) new to, or wishing to move into, applications/research areas affected by SBLIs and who need a thorough introduction. Also useful for individuals somewhat familiar with the basics but need to deepen their understanding. Undergraduate-level knowledge of fluid mechanics (incompressible flow, viscous flow, basic gasdynamics) is expected.
General Course Information:

  • Course Level: Fundamentals/Intermediate
  • Course Length: 2 days
  • AIAA CEUs available: yes
  • Review of fundamental physics
    • What is compressibility?
    • Basics of Gasdynamics
    • Compressible viscous flow
    • 3-dimensional separation
    • Exercise (basic gasdynamics, basic viscous flow, interpretation of real data)
  • Classification of SBLIs
    • 2-dimensional vs 3-dimensional transonic/supersonic/hypersonic
  • Fundamentals of 2-dimensional interactions
    • Basic physics of normal SBLI
    • Basic physics of compression corner
    • Basic physics of impinging shock interaction
    • Laminar vs turbulent and transition effects
  • Fundamentals of 3-dimensional interactions Separation
    • Free interaction theory
    • Glancing interaction / sharp fin
    • Blunt fin
    • Swept Compression corner
  • Exercise (contrast viscous/inviscid flowfields, interpret/analyse actual experimental data)
  • SBLI control
    • Introduction: Types of control (BL- vs Shock-control)
    • Boundary layer controls
    • Shock controls
  • 3D/corner effects on ‘2D’ interactions
    • Transonic normal SBLI
    • Impinging oblique SBLI




Holger Babinsky originates from Bavaria and studied Aerospace Engineering at Stuttgart University in Germany. He obtained a PhD in hypersonic aerodynamics from Cranfield University (UK) in 1994. After 18 months as Research Associate at the Shock Wave Research Centre of Tohoku University in Sendai, Japan he returned to the UK to take up a position at the University of Cambridge. He is now Deputy Head of the Engineering Department, Professor of Aerodynamics and Chair of the Fluids Group as well as a Fellow of Magdalene College. His main areas of research are in the field of experimental aerodynamics and associated measurement techniques. Apart from shock wave/boundary layer interactions, which he has studied for more than 20 years, his current research includes the aerodynamics of micro-air vehicles, road vehicles, wind turbines and flow control for transonic aircraft wings and supersonic engine inlets. He is a Fellow of the Royal Aeronautical Society, an Associate Fellow of the American Institute of Aeronautics and Astronautics and a member of several RSO (NATO) advisory groups. He has supervised more than 30 PhD students, authored or co-authored more than 50 articles in international scientific journals and contributed over 100 papers to archival conference proceedings. He has received a number of awards for his teaching, including Cambridge University’s Pilkington Prize. He has co-authored (with Professor John Harvey, ex Imperial College) the first textbook on shock-wave/boundary-layer interactions, which is currently being translated into Chinese.


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