A Life with Shock Waves (Ernst Mach Memorial Lecture)

Abstract

In 1957, the author obtained his first flow pictures in a shock tube; paper will retrace the history of a life-long involvement with the field. The first motivation was to use the shock tube as a short-duration aerodynamic test facility, a goal to be belately achieved, with results on e.g. hypersonic flow around flared bodies, or transonic motion of permeable airfoils. In the meantime, two shock tubes and a large facility, combining the shock- and Ludwieg-tube concepts, were built, as well as the necessary measuring equipment. In the same area, a development of the Ludwieg-tube principle, offering a five-fold gain in test time, has been proposed. Our interest centered then on the problem of shock diffraction around obstacles, and in ducts and cavities; for weak shocks, our theory is in excellent agreement with experiments. For the diffraction around a convex corner, a configuration was discovered, which delays BL separation. Shock focusing, amplification, and stability were investigated; a “shock nozzle” was devised, and also an improved version of the spiral contraction. Recently, the author joined Prof. Raymond Brun’s Marseille team working on the development of a new Stalker-tube facility; already, very strong shocks (M _S = 18.5) were obtained in air, and a new shape for the piston was devised, to minimize pressure disturbances caused by accoustic resonance inside the compression tube.