Behavior of the Shock Wave Propagating in the Small-Diameter Tubes

Recently, the micro-shock waves have attracted attention from researchers in several fields of science. It is well known that the shear stress and the heat transfer between a test gas and a wall lead to significant deviations from the normal theory of a shock wave propagating in a small-diameter shock tube [1, 2]. In our first research, we developed a diaphragmless driver section using a rubber valve, and estimated the valve opening characteristics as the first step towards clarifying the shock wave characteristics propagating in the small-diameter tube [3]. As a second step, the shock wave measurements in small-diameter shock tubes were performed at a relatively low driver pressure by using the driver section with rubber valve [4–6]. However, at relatively high driver pressures over 0.5 MPa, shock wave measurements using the diaphragmless driver section with rubber valve are very difficult to perform, because of the structural properties of the rubber valve.