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Training workshop @ University of Cambridge: Introduction to shock-wave/boundary-layer interactions

23rd October 2023
Department of Engineering
University of Cambridge
Prof Holger Babinsky

*This workshop is now closed for applications*

The NWTF would like to gauge interest for this training workshop – dates are provisional. Please email [email protected] to register interest in attending. Dates are subject to change.

This course is a 2.5 day, intensive short course introducing the interaction between shock waves and boundary layers, an ubiquitous element of compressible flows. The course will be of use to graduate students, researchers and engineers interested in high-speed aerodynamics, as shock boundary layer interactions (SBLIs) occur throughout high-speed aerodynamics and high-speed propulsion. Typical applications include both external and internal supersonic flows, rocket nozzles, aircraft wings, gas turbine blades, rocket aerodynamics including separation of stages, and boosters, ramjets, scramjets, ballistic aerodynamics, aircraft intakes, etc.

The first part of the course begins with an overview of compressible flows, introducing some fundamental boundary layer and gasdynamic concepts. Classifications of the various types of SBLIs are introduced next. The physics of 2D SBLIs then explained in detail, illustrated with examples from literature.

The second part introduces more advanced topics, such as the difference between laminar and turbulent SBLIs, unsteadiness and hypersonic aerodynamics. Specific 3D SBLI problems are detailed next. Finally, control strategies for SBLI are discussed with a few case studies as examples.

The course will be aided by practical demonstrations in the Cambridge wind tunnel and a problems, which will be discussed in a tutorial session.

Objectives of the course:
The main aim of the course is to give a good understanding of the physics of shock wave boundary layer interactions. A student of this course will be able to classify the type of SBLI and comprehend the basic physics governing SBLIs in 2- and 3-dimensional problems. The course also aims to give an introduction into various advanced topics such as SBLI unsteadiness, SBLI control, and hypersonic flows.

1. Review of basic compressible flow
What causes compressibility?
Compressibility effects in transonic airfoils
Shock waves

Laboratory Demonstration: Transonic airfoil

2. Review of basic viscous flow
What viscous effects cause compressibility?
A little boundary layer physics
Compressible boundary-layers
3-dimensional separation

3. 2-dimensional Interactions
Classification of SBLIs
Normal SBLIs
Fundamental physics (attached, incipient, separated)

4. 2-D SBLIs cont.
Normal SBLIs in practical applications
Normal shock-diffuser
Compression corner
Impinging/oblique shock reflection

Laboratory Demonstration: Supersonic compression corner

Question sheet 1

5. Related topics
Free interaction theory
Laminar vs turbulent SBLIs
A few comments on hypersonic flows

6. 3-dimensional interactions
Sharp fin
Blunt fin
Swept compression corner
Double sharp fin

7. Corner effects
In normal SBLIs
For oblique reflecting SBLIs

Laboratory Demonstration: Supersonic compression corner with corner separation

8. Control of SBLIs
The need for flow control
Principles of SBLI control
Boundary-layer control
Shock control

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