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The present work is aimed at experimentally investigating both the development and the oscillation phenomena of pseudo shock waves in a two dimensional asymmetric nozzle. A shock tube was used to generate supersonic flows in nozzles which consisted of both short and long walls diverging in the flow direction. Two kinds of nozzles were tested; one with both side walls of the nozzle diverging (Model A) and the other with only one side wall diverging (Model B). Nozzles were connected to a duct with constant cross sectional area. Initial pressures in the test section were 25, 50, and 100 kPa and the initial flow Mach numbers, before the diverging section were about 1.2 for model A and 1.4 for model B. The flowfield in the supersonic nozzle was visualized sequentially by schlieren photographs to observe the development of a pseudo shock wave and also the unsteady motion of this shock wave oscillating in the flow direction.

In the present paper the decay of shock waves propagating in a kinked exhaust pipe was investigated by numerical simulations based on the TVD scheme. In order to clarify the validity of the present computational model, the numerical results on blast waves propagating in a kinked duct were compared with the experimental ones. Various initial conditions as well as mesh sizes were examined to simulate exploding wire experiments. Shock wave geometry based on computed density contours showed qualitatively good agreement with the schlieren photographs. Measured pressure changes across the shock front also showed good agreement, when they were compared quantitatively with computations on the upper and the lower walls, and on the center line along the ducts. The present simulation model putting a narrow high pressure region as initial conditions in a duct was useful to simulate blast wave propagation.