A Perspective of Shock Waves for Gasdynamical and Granular Flows

Shock waves are a common event in supersonic gasdynamical flows as well as granular free-surface flows at supercritical speeds when the flow is deflected by an object. There are strong comparisons and distinctions between these two types of flows, and we wish to address a few aspects of the difference between gasdynamical and granular flows below. We begin by comparing their oblique shock relations, in which weak, strong, and detached shock waves can be created in both scenarios. However, even if the upstream Froude number of granular flow becomes arbitrarily large, a granular shock wave will remain attached and oblique around a wedge with a deflection angle of 90°, whereas an attached gasdynamical shock wave is limited by a maximum wedge angle of, say, 45.6°. The shock standoff distance for a detached granular shock wave, on the other hand, tends to become infinitely small as the upstream Froude number increases because it is associated with the flow height ratio across the shock wave, whereas that of a detached gasdynamical shock approaches a constant value due to compressibility limitations. Finally, an example of shock interaction is provided, implying that a complex shock system could cause some flow instability.

Author(S) Details

Xinjun Cui
Department of Engineering and Maths, Sheffield Hallam University, UK. .

View Book:- https://stm.bookpi.org/NPER-V8/article/view/6114

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