EXPERIMENTAL STUDY ON THE CHARACTERIZATION OF TRANSVERSE JET INTERACTION IN HYPERSONIC RAREFIED FLOW

Jet interaction is an effective approach for hypersonic flight controls with higher agility and improved maneuverability. Previous researches are mainly focused on the mechanisms of jet interaction effects in continuous region, classical flowfield structures of jet interaction based on different models have been proposed theoretically, on the other hand, scarce experimental data on characterizations of jet interaction in rarefied region exist. Therefore, the objective of this work aims to experimentally investigate the effects of jet pressure and hypersonic rarefied flow condition on the characterizations of transverse jet interaction based on a flat plate model, whereas hypersonic rarefied flows are generated in a JFX detonation shock tunnel. Evolution and typical structure of transverse jet interaction in hypersonic rarefied flow are recorded using high-speed schlieren imaging approach, and variations of spatial positions of different shock waves are analyzed using imaging process technique. Compared to the flowfield without the presence of jet flow, the interaction between jet flow and hypersonic rarefied flow makes the flowfield much more complex. Oblique shock could instantaneously penetrate through the flowfield of jet interaction due to the pressure fluctuation of jet flow caused by the incoming flow. With increasing the jet pressure, the affecting region of the barrel shock gradually becomes broader. The spatial position of the oblique shock wave in the upstream of the triple point barely changes with an increase in the jet pressure, while in the downstream of the triple point, the bow shock moves upstream with increasing pressure. The spatial position of the barrel shock would not overlap with the other two when the jet pressure is low. The pressure reduction of the incoming hypersonic rarefied flow can broaden the affecting region of the barrel shock and thus move the bow shock upstream as well, but it has little influence on the spatial position of the oblique shock wave.