2508 軸方向圧縮を施した2次元Dual Bellノズルモデルの始動停止時における流れ特性(G05-2 噴流(2),G05 流体工学)  [in Japanese] 2508 Flow Characteristics of Two-Dimensional Compressed Dual Bell Nozzle Models during the Startup and Shutdown Transients  [in Japanese]

In the present paper, the experimental and numerical investigations are described to clarify how the axial compression of the extension nozzle influences on the unsteady flow fields and side load in startup and shutdown transients for a 2D dual bell nozzle models. In the experiments, the flow fields are visualized and recorded by the schlieren method and the high-speed camera, respectively. The side load is measured by a strain gauge. The three flow patterns are observed. The strain gauge measurements indicate that side load was produced by transitions between the two flow patterns of the three. The numerical simulations show that the jet oscillations cause the side load oscillation, and result in the asymmetric jet pattern, which causes a impulsive large side load. Moreover, the stronger axial compression of the extension nozzle makes the more quick separation point movement, and results in the larger side load.