A Perspective of Shock Waves for Gasdynamical and Granular Flows | Chapter 08 | Novel Perspectives of Engineering Research Vol. 8
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 shoc...