151-0110-00L  Compressible Flows

SemesterSpring Semester 2015
LecturersJ.‑P. Kunsch
Periodicityyearly recurring course
Language of instructionEnglish


AbstractTopics: unsteady one-dimensional subsonic and supersonic flows, acoustics, sound propagation, supersonic flows with shocks and Prandtl-Meyer expansions, flow around slender bodies, shock tubes, reaction fronts (deflagration and detonation).
Mathematical tools: method of characteristics and selected numerical methods.
ObjectiveIllustration of compressible flow phenomena and introduction to the corresponding mathematical description methods.
ContentThe interaction of compressibility and inertia is responsible for wave generation in a fluid. The compressibility plays an important role for example in unsteady phenomena, such as oscillations in gas pipelines or exhaust pipes. Compressibility effects are also important in steady subsonic flows with high Mach numbers (M>0.3) and in supersonic flows (e.g. aeronautics, turbomachinery).
The first part of the lecture deals with wave propagation phenomena in one-dimensional subsonic and supersonic flows. The discussion includes waves with small amplitudes in an acoustic approximation and waves with large amplitudes with possible shock formation.
The second part deals with plane, steady supersonic flows. Slender bodies in a parallel flow are considered as small perturbations of the flow and can be treated by means of acoustic methods. The description of the two-dimensional supersonic flow around bodies with arbitrary shapes includes oblique shocks and Prandtl-Meyer expansions etc.. Various boundary conditions, which are imposed for example by walls or free-jet boundaries, and interactions, reflections etc. are taken into account.
Lecture notesnot available
Literaturea list of recommended textbooks is handed out at the beginning of the lecture.
Prerequisites / Noticeprerequisites: Fluiddynamics I and II