Compressible Flows

Project: Research project

Description

The research in this field is focused on the computation of the propagation of intense shock waves. Thereby, expanding as well as the converging waves are considered. The individual studies investigate several effects which may have a significant influence on the flow behind the shock. In particular, the influence of real gas behaviour, radiation, varying density and pressure ahead of the shock, and the contamination of the gas with solid particles are considered. The solutions are mostly obtained within the framework of self-similarity. In some cases the temporal scope of these self-similar solutions is extended applying a perturbation method. The perturbed similarity solutions serve as appropriate initial conditions for the computation of the entire history of the wave propagation ranging from the intense shock to the acoustic wave regime using the method of characteristics.

Experimental work in the field of compressible flows is concentrated on investigations applying optical techniques, especially the Schlieren method. This technique allows evaluating the performance of Laval nozzles by visualizing the flow behaviour after the nozzle exit. The recorded wave pattern at the nozzle exit can be used as an indicator to check if possibly normal shock waves occur inside the nozzle, if oblique shocks emerge from the edges, or if the desired characteristic is achieved, i.e. a fully supersonic state with nearly parallel streamlines. The test rig is also applied in laboratory courses to introduce students into the concept of Schlieren methods and to demonstrate compressible flow behaviour.
StatusActive
Effective start/end date1/01/95 → …