In the footsteps of Ernst Mach ? A historical review of shock wave research at the Ernst-Mach-Institut

Abstract

Abstract. The aim of this paper is to recall some of the historical work on shock waves and to give a brief survey of research activities at the Ernst-Mach-Institut (EMI). Some fundamental results of Ernst Mach (1838Mach ( -1916 are demonstrated and historical remarks are given to the shock tube as an important tool in shock wave research. The activity at EMI in this field was initiated by Prof. H. Schardin (1902Schardin ( -1965 in 1955 and has since been continued. Propagation processes of shock and blast waves, blast loading phenomena, shock attenuation, shock reflection at various surfaces, development of new types of blast simulators, electromagnetically driven T-tubes, precursor and decursor phenomena are only a few examples of research topics at EMI that will be discussed.

Fluid Mechanics and Homeland Security

“…There is also a special opportunity here for cheap, safe, quick simulations of blast effects using scale models and optical shock wave imaging. Such scaled experiments compare well with costly, dangerous, time-consuming full-scale tests (Edwards & Owen 1995, Reichenbach 1992, Smith et al 1992. High-speed digital video cameras are now available to record shock position versus time by schlieren or shadowgraphy (Settles 2001), from which all postshock fluid properties can be determined.…”

High-Speed Schlieren Imaging of Vapor Formation in Electrospray Plume

“…In order to enable the direct observation of electrospray vapor, an optical technique called schlieren photography was adopted in this study. Schlieren refers to the transparent inhomogeneous media which have very small refractive index differences with respect to that of the surroundings, for example: strong air flows, 54 shock waves, 55,56 nonuniform glass, 57 and vapor. 58,59 Due to small refractive index gradients, illumination changes�caused by these objects�are usually barely visible by naked eyes or direct shadowgraphy.…”

“…In order to enable the direct observation of electrospray vapor, an optical technique called schlieren photography was adopted in this study. Schlieren refers to the transparent inhomogeneous media which have very small refractive index differences with respect to that of the surroundings, for example: strong air flows, shock waves, , nonuniform glass, and vapor. , Due to small refractive index gradients, illumination changescaused by these objectsare usually barely visible by naked eyes or direct shadowgraphy. , Thus, schlieren imaging was developed as early as in the 17th century to observe the invisible. ,, It is able to differentiate the small deflection of light pathways caused by passing through the invisible state and visualize them as shadows on the viewing screen. Conventionally, a schlieren imaging setup is composed of a point light source, one or a few collimating and focusing mirrors, an edged knife, and a viewing screen/camera system. , Light rays, emitted from a point light source, traverse the schlieren, focusing around the knife edge, and cast on the viewing screen or camera.…”

Shock tunnel flow visualization using planar laser-induced fluorescence imaging of NO and OH

“…Historical reviews by Oertel (1983) and Reichenbach (1992) indicate the extensive use of classical flow visualization in the study of transient supersonic flow and shock phenomena. The process of shock reflection and nozzle starting or jet development in a planar nozzle with a rounded or sharp inlet, a transition nozzle, and an orifice plate was examined in detail by Amman and Reichenbach (1973), who obtained temporal sequences of shadowgraphs of these shock tunnel flows.…”