Cold gas simulation of a solid propellant rocket motor

The objective of this study is to characterize experimentally the mean and fluctuating flowfield and the dynamic instabilities that develop along a two-dimensional channel with porous walls, The channel is a 1/40 scale model of the ARIANE 5 segmented solid rocket motor. This cold gas simulation is based on an aeroacoustic similitude that reproduces the Strouhal and Mach numbers and the complex internal geometry (obstacles, flowing cavity, submerged nozzle) of the full-scale motor. Measurement data, mean and fluctuating velocities, and shear stresses were obtained using a two-component laser Doppler anemometer, The injection wall, composed of a sintered Poral and of a metallic weaved sieve, gave a uniform injection velocity, with a controlled injected turbulence intensity. The second obstacle divided the flowfield into two regions. Upstream, the how was laminar. A shear layer developed at the top and in the wake of the obstacle because of the interaction of the upstream main flow with the downstream injected flaw. Downstream of the obstacle, velocity fluctuations increased and the shear layer became turbulent.